I have a 2nd generation XP Pen Artist 13. It’s a great tablet and I’ve managed to make it work with my Steam Deck too.
But…
It’s basically an external monitor with pressure sensitive surface, so still less portable than an actual stand alone table. So I’m wondering if there is a tablet with a pressure sensitive screen and battery free pen that either comes with Linux or can install Linux on.
The programs I use for making art are Krita, Gimp, and Blender 3D.
It’s not exactly what you are looking for, because the pen is not battery free, but the star lite is a surface style convertible that ships with Linux out of the box. And it supports MPP pens
https://starlabs.systems/pages/starlite#