Live plants (and the soil they grow in) are great for helping out with humidity. They also grow and provide cover and enrichment.
If you just want to provide one snake with the best possible care, get the biggest viv you have room/budget for, make the effort to heat and humidify it appropriately, fill it with hides, plants, ledges, tubes, burrows, etc. Put nice lighting in it on a timer. Yes, it takes a little more thought, planning, and $$ to heat a bigger cage, but it's not *that* hard. Yes, you will have to fill all that space with stuff so your snake can feel secure. Provide a choice of hides at various temperatures and humidity levels.
For cleaning, a large cage is actually possibly easier to spot clean than a smaller one because there's less chance that the snake will sit on top of the poop or smear it around. And the snake is actually able to get away from its waste and go somewhere else. Or you could make it bioactive, in which case it cleans itself.
Yes, ball pythons need tight hidey-holes to feel secure in and do not care for wide open empty spaces. But you absolutely can provide for that in a big cage as long as you don't just leave it big and empty.
Obviously it's also possible to do those things with more than one snake, too. But you asked about pouring all your energy into giving one snake everything you possibly can.![]()