First: Good work on your bench so far. The form is quite good and you've clearly worked hard. I'm also very happy to see you trying to do anything you can do to get better (for example making the effort to film yourself and ask here for advice).
For the most part, your bench form is perfect, so I am only pointing out minor things below. I did not have a problem with your hip area: in powerlifting the goal is to lift as much as you can without breaking the competition rules, and this means that your whole body should be doing everything it possibly can, to help you do the lift without allowing your head, shoulders, or bum to leave the bench or feet to leave the floor (since these will cause the lift not to count). As a competition judge, I would have counted each of your lifts because the bum was never visibly off the bench (though there was a vertical metal rod in the way of me seeing properly in the second video!). Your elbow position was no major red flag for me, in fact the angle was rather appropriate for someone whose goal is to lift as much as they can (more on this when I describe the feet position later in this answer).
So here are some minor pointers:
1) The pause at the bottom may not be sufficient in competition. There will be someone calling 3 commands "start", "lift", and "rack". If you don't train this way, you may not even be able to do 230 lbs in the competition despite you doing 230 lbs quite comfortably in the video you posted. You have to be able to hold the bar steady for long enough while waiting for them to call the "start" command, then keep the bar steady on your chest for long enough for them to call the "lift" command, and then you have to hold the bar steady at the end of your lift until they call "rack". Your spotter can call these commands for you in order to simulate the competition. People that do not do this, tend to be able to lift significantly less in competitions than in the gym. At the 1-rep max, it makes a huge difference.
2) There is no excuse not to use the side clips (in both videos I see them right there on the weight rack). As you do your reps, the weights can move slightly. Everyone has a slightly stronger side, so the weights will move asymmetrically and will not only change the moment of inertia (distribution of mass) but it will also change the location of the centre of mass, which is something you certainly do not want, when you get to your heaviest sets. In competitions you will have IWF standard 2.5kg collars as in this video: https://www.youtube.com/watch?v=MxgqzyIj2Dw. Some gyms will have these, and otherwise if you really want to simulate the conditions of the competition (think about how having these 2.5kg collars changes the moment of inertia) you can buy them for not much, but for most people the clips you have next to your bench are sufficient.
3) The person giving your lift off is actually lifting the bar vertically a bit, which at 1-rep max level, can actually destabilize after you spent so much time getting your shoulder blades and hands into perfect set-up position. In the competition video I just sent you, not everyone chooses to get a lift-off, but a good example is at 37:48 when the lift-off is not vertical at all (only horizontal). It shouldn't really be called a "lift-off" but maybe a "push-off". This might be hard for your spotter to do, but it should be easy for him to do it like the person doing the lift-off here (it's a much smaller guy, with a much smaller 1-rep max, but most of what you see here also applies to anyone's 1-rep max): https://www.youtube.com/watch?v=oJjTs89UOj0. This is also a better example of how you want the spotter to spot you. Not with their hands around the bar on the way up like your spotter did. When you get to the heaviest you can lift, the brain and mind become even more important than your muscles (how else can someone like Lamar Gant at 56kg be deadlifting over 300kg?). You need to train without the mental reassurance that there's a hand right there (without being able to see the hand, you may have some anxiety about whether or not the spotter is really 100% there, and anxiety can hurt your lift, so you should practice with this anxiety of not being able to see the spotter's hands .. if you're worried about safety, see my paragraph 4 below). Also having hands in your line of vision, can be mentally distracting, which also hurts your lift.
4) Notice in the competition video the bench has two things on the side to help catch the bar if you can't lift it. Your bench is in a lifting cage with holes where you can put metal bars, which is especially important since you only have a back spotter rather than 3 spotters (1 at the back and 2 at the side).
5) You said the heaviest you've done for 1-rep max was 235 lbs, so it's a surprise that you're not using calk on your 230 lbs lift which is only 5 lbs less than your personal record! My guess is that with proper training and chalk, your 1-rep max really could be 250 lbs, and that when doing 5 lbs less than that (245 lbs) you'd definitely be using chalk (see the people in the videos I sent).
6) Breathing: Before lift-off you want to take a huge breath. To simulate this, hold your breath completely for 2 minutes and then take the biggest breath you can possibly take. Practice this (it's also what musicians of wind instruments do). You want to have enough air in your body to last for a long time, since in competition you have to hold the bar at various positions for lengths of time while waiting for commands to be called. The bench press (in powerlifting) is a long exercise, for which you'll need oxygen for a long time. I also take a huge breath right before my heavy deadlifts and squats, I find I can lift the heaviest amounts with greater success when I do this.
7) Your whole body should be tight. Shoulder blades as if they were holding a penny between them, all muscles ready to go to war with the bar. I am a big fan of your lifting, but you look more relaxed even for the 230 lbs lift, whereas the person doing the 80kg 1-rep I showed you looked very tight (still far from professional level but this looks more like what 5 lbs less than 1-rep max should look like). Your real 1-rep max is probably 250 lbs, but you think it's 235 lbs because you haven't practiced the full-body tightness enough.
8) Shoes. I know that some of the lifters in the competition video I sent, are wearing their squat shoes, but I wouldn't recommend that, especially in 2020 when better alternatives are available. Squat shoes are only for squat (and even optional at that!), and not for deadlift or bench. For me and most people, lifting is done best with just socks, which helps with proprioception (same reason why you can bench more with bare hands than with gloves). In a competition you will need to have more than just socks, so I recommend something like vibrims (which have only become widely available relatively recently, which is why you don't see them in that competition video).
9) Angle of your legs: I will have to add more about this later (with diagrams) but I have now spent a lot more time on this answer than anticipated and am now very late for the meeting I had planned today! I think you (or someone else) already mentioned knowledge of the need to dig in with your heels. The effect of this is not optimal unless the angle of your legs is optimal, meaning that the force obtained from digging in with your heels, is used nearly 100%, rather than only (100% x cos(A)) where A is the angle and cos(A) is the cosine of it. It is for this reason though, that I say your elbows are in good position (roughly 90 degree angle). cosine(90) = 1, so your elbow angle allows less of your force to be wasted.
10) Perhaps try to work a bit more on your ability to keep the bar in control. You had complete control over the bar on the way down on your 225 lbs lift, but at 230 lbs, it was good at first but towards the end of reaching your chest, it began to look like the weight of the bar had more control over the situation than you did! It started dropping faster and you can see that you lost a bit of stability (one side started falling more than the other side, for example).
Overall your lifting form is almost perfect as it is, so everything above is not meant to attack you in any way, they are just minor tips (along with the videos where you can see what professionals look like, or in the second case, an amateur that looks almost ready to do his first competition).
It would be nice if you could find a group of other people that plan to enter the same competition as you. You should have 2 side spotters and one back spotter for the squat and bench, and one person calling commands. Your "team" of 5 people will rotate your sets, such that the two people loading each side of the bar, are not doing their lifts until 2 sets later. This way you're not wasting energy loading the bar right before your set. I can try to find people I know in Winnipeg if possible. But for now, kudos to your spotter for helping you get stronger.