For a first jam with no background, it’s impressive that you were able to make as much as you did. You definitely should be proud of what you achieved.
I definitely look forward to seeing future games you create! I understand not having the time for a post-jam update.
On the note of physics, in this case I’d probably let the player pick up the boxes somehow, to sidestep the physics a bit. Don’t feel bad about the physics though, they’re always a mess, I know from experience, especially with Unity.
Again, good job doing everything you did in just a week!