The answer is, "Yes."
You should use all of the above.
The biggest mistake people make when training is assuming one technique is better than another. In reality, it's typically the combination of different techniques that yields the best results. For example, my experience as a fitness trainer was that someone who rotated between dumbbell, barbell, and smith machine would have far more success increasing strength and building muscle than someone who simply focused on one.
Each has trade-offs. A beginner or someone training without a spotter may want to use the Smith machine. It is the most stable solution and many models are self-spotting. The trade-off is that it locks you into an unnatural range of motion.
The barbell is a free weight but as a bilateral movement requires less stabilization than the dumbbells. You can typically load a heavier weight and experiment with various grips. The exercise will focus on the core movement of pressing the weight, unlike the dumbbells that require far more stabilization and coordination/balance.
The dumbbells work well and will involve different muscles. You are likely to engage your core more to maintain balance and stability and typically involve more shoulder as well.
No matter what you do, I HIGHLY recommend hiring a trainer even if just for a single session to train proper form. You can read and watch all of the videos you like, but there is no substitute for someone there who can evaluate your level of fitness and watch your form and provide feedback. I strongly urge this because if you guess and try to do your best there is a chance you could be doing it wrong and creating a bad habit that can set you up for injury later. As for the technique, it is important to learn proper benching technique including how to engage your scapulae because failure to stabilize correctly can lead to rotator cuff injury.