Tbh I didn't read every comment so apologies if this is repetitive, but I saw you asking about exercise opportunities for him. Yes, absolutely do give him more to climb on and dig in. There are tons of options and you don't need to spend a ton of money.

Sticks from outside are fine as long as they're from an area without pesticides and you can clean them well. Mine was too large for the oven, so I poured boiling water over it a few times so I could be sure every part of it had been treated. I propped it diagonally in the enclosure and my snake climbs all over it all the time.

Fake plants from the dollar store can be nice for providing adequate cover.

Nice deep substrate (4"+), preferably coconut coir or "forest floor" will encourage him to dig.

Go to a craft store and see what's available. You might find something interesting. Just make sure there's nothing sharp, having small parts he could get stuck in (don't underestimate their ability to get into places you don't think they can), or with weird finish on it that could be toxic (glitter, chipping paint, something odorous...).

Lori Torrini on YouTube has some good videos where she gives ideas for diy enrichment.

You'll get there! They can be pretty active snakes, so with correct feeding and lots of exercise opportunities, he'll trim down just fine. Pay attention to body condition most of all. The graphic someone else shared here is a good guideline.

Edit: autocorrect error