Ah I have a bug then : i'm using a surface pro 7 win11 and an onscreen pen but it draws at most points...
like for it to draw anything using my pen I have to just "click" and it only makes a point (with the size and color of the pen), if i hold and drag it doesn't draw anything, like i see the mouse position following a bit before going back to the position where the pen touched first and it doesn't draw anything and also some icons in the bottom right of my task bar begins flickering xD
I tried with the pen tool in both mouse slots (idk the official words x) ) and everything works well with my mouse and even with touch