There are a lot of different things you can do, and I wouldn't try them all at once.

The first thing I would do is get digital thermostats and put a piece of melamine on the second level to limit her to the first level of the cage and see if your temperatures are correct using the digital thermostat. If your temps are okay from there I would work on getting the humidity to where you need it. Putting the water dish over part of the heat pad should help with that.

If you can get one level correct, then you can convert the other two levels into addition cages for two more ball pythons.

Don't try too much at once, that's when you get overwhelm. Break things into smaller steps and work from there. Good luck.