New PacMan enclosure, tips for humidity and other things?

Hello! Back again lmao. I just got my pacman on Thursday I had her in an 10 gallon tank that wasn't really cutting it. So I purchased an 18x18x18 tank today and moved her.

Here's a link to a photo of it https://bsky.app/profile/pegasins.bsky.social/post/3ldd22ioqys2y

Hopefully that's ok idk how to use Reddit.

I made a previous post about her sleeping in her dish at night, and I got a small floor heater that's keeping my room temperatures much better, minimum 75F.

I have a digital hygrometer and thermometer, and I'm using a 26watt exoterra UVB bulb. But I'm noticing that that I'm struggling to keep her humidity above 60%. I have an automatic misting system that's coming in tomorrow so I don't have to worry about her while I'm at work. But I'm just concerned that the humidity seems to be dropping rather quickly. The substrate is a mix of top soil and coconut husk/fiber

If anyone has some suggestions let me know. Also anything to help improve her enclosure overall would be great. Tysm for your time!