What are you training for? For fitness or do you want to actually compete on a competitive level?

I'm by no means a professional, but I've been doing this a little over a month and have been taking it very seriously. If anyone finds fault in my logic and reasoning please let me know!

I can't tell what kind of boxer your are because you square yourself up a lot, that is to say, you stand in front of your target with the entire width of your torso in front of them. Squaring yourself up happens naturally during an execution of combinations or just normal power punching, but you stay squared even when NOT punching. It's bad form to be squared so much because that gives your opponent more target areas and makes it extremely difficult for you to defend as a result.

I can't tell if your hands are wrapped properly, are they? Improper hand wrapping can result in injury ranging from minor to severe, so if you haven't learned how to properly wrap your hands, please do so!

You keep your chin out as long as a crane! That's going to get you hurt 100% of the time in a fight or (goodness forbid) a real confrontation. Try to tuck your chin in a little more so that you're looking at your opponent through your eyebrows.

I also notice in your first and second video that you dipped...really abruptly and low, perhaps this is just something I haven't learned but I don't see how that works into a heavy bag workout. And if I recall correctly, dipping below the belt is illegal.

If you'd like to pursue this as a serious hobby or even compete, I suggest you learn the fundamentals 1 at a time. It's critical that you put focus into one thing at a time because it helps you tie every other technique you learn thereafter. It's like math and science!

So start with learning a proper stance/balance, then get into the basic punches and combinations. Start literally from the ground up!