Congrats on making it through the box challenge! I'll be taking the helm of your critique.

So first of all let's get the elephant out of the room, your convergences. They're not awful. Most of the time you manage to get them to converge even if the rates happen to be different like in your first boxes. But you still manage to create divergences instead of convergences and sometimes they just come out parallel. Remember that even though the actual box itself is made of parallel lines, perspective affects the box and makes those lines converge to a single point.. Three point perspective boxes have every vp converging, it's not like 1 point or 2 point where some are infinitely parallel. You should follow this guide for a better step by step understanding on how to make sure your lines always converge.

Your lines are a bit wobbly but that's fine, you're still adjusting to using the shoulder (even though you should've been making sure to use it rather than the elbow from the start of lesson 1), just make sure to apply more confidence in the future.

An additional thing you started to do but began to avoid which I appreciate, was creating correction arrows on your early boxes. This is unnecessary, the extension lines should be all you need to correct yourself if you went wrong somewhere. Drawing too many lines rather than what you need will impede your learning and just make you more confused. try to avoid doing these in the future as mentioned just now, they're unneeded and not part of the challenge nor your learning.