The explicit intent for Stronglifts 5x5 is to be a beginner's strength program that exploits linear progression to get people used to performing the big three lifts (squat, deadlift, bench). It does this by starting off really easy to give people time to learn the basic movements then it slowly ramps up little by little each training session. It does this very well despite being very plain and boring.
Because it starts off so easy and it's so plain and boring, people will often supplement it with other stuff. Then they stop progressing in SL because the other stuff makes them too exhausted.
SL actually does become incredibly hard and exhausting after a few months on the program if you continuously increase the weight each training cycle like it's designed. Because of that, I would say that on days you do SL, do SL as prescribed with the additional bench sets that are prescribed in the Barbell Medicine's press plugin. The overall length of the session shouldn't be longer than an hour, maybe 90 minutes tops if you have long rest periods (you don't currently, but you'll probably increase it as weights get heavier).
Since SL is only three days a week, you can do accessory work on the days in between. You can get away with not doing legs or ab accessories since you're squatting three days a week and sometimes deadlifting twice a week. So that limits what you can do. Overall the accessory day would be about 45 - 60 minutes.
So overall you would go from doing 2+ hours three days a week to about 1 hour five days a week. Or more accurately, one hour three days a week plus two optional one hour days.