Ok I'm gonna make a suggestion I rarely ever see, I've been using this program for years on my Note series phones (since the Note 3!!) and it's called ArtFlow Studio. It's a little bit quirky, but it's a one-time purchase. On my new Galaxy Tab S7+ it's able to make file sizes just over 6000 pixels square. It's got layers, programmable brushes, and can export layered PSD files. It's missing some bells and whistles and some standard stuff is a little "hidden." The S-pen works great as far as tilt and pressure. Buy the full version, it's SO worth it. I think it's a single developer who made it. I've tweaked some brushes to be able to get really nice results.
I LOVE Clip Studio, which I have also been using for years (from back when it was Manga Studio), but the prospect of having to pay a monthly fee just to use it on my tablet is really putting me off. One of the reasons I have dumped Adobe is the subscription model.
If anyone has good suggestions for vector programs I'd love to hear it!