Ive had (temporarily) humidity in the 90%s for days With no issues. As long as the snake isnt physically wet, i think high humid air is good for ball pythons.
I aim for 55-70%. I would rather have high humidity than low. I only worry if the enclosure floor or the walls are literally wet from condensation or water bowl spills.
Also, I’ve switched substrate multiple times and the pythons don’t seem to care at all. My snakes are pretty “chill dudes” as long as the the temperatures are perfect. That is the one thing that they get pissed about, (temps being off). so ive made sure to perfectly tune my temps.