Tell you what- many years ago, the best & smartest dog I ever had or knew came from a shelter at 6 mos. of age- she was a whippet-shepherd mix with a HUGE need for activity, for a job, & she was very focused. She was the sort of dog that drove most people nuts...so maybe that explains a lot about me, lol. She was tireless about finding & fetching things & would have made a great working-search dog. I managed to channel her hyper-energy with training & regular work-outs, & as a result, she was never destructive, & incredibly smart & easy to live with- but she REQUIRED regular exercise & attention. It's a bit like the warning they give for Border Collies- another dog that needs to work, but they're herders; still, when it comes to having a really smart dog, "be careful what you wish for"!

You may not get any rest.
I know we're not talking about dogs here, but hear me out: I've also seen some homes custom-modified for their cats, with "cat-walks" (high on the walls, shelves & tunnels, etc) throughout the home, going from room to room, that obviously kept their indoor cats busy- exercised & happy. People do that for pet ferrets too- they sell flexible tubes for them to explore & run thru- a bit like the "Habitrails" they sell for hamsters, only much bigger. They also make tunnels for training dogs- can't say how sturdy they are, but you may need to borrow something from other kinds of animals- something obviously sturdy & securable. (If it could be locked as a "closed loop" for snake exercise...maybe?)
I'm not saying this is convenient or easy- after all, you chose the snake, not me- but maybe you could make something where they could get hours of exercise? It might take a room, but hey? At least give it some thought. Snakes are not built to be stationary objects of our admiration. Not even BPs, but their needs are much easier to meet.