I still use the Paint from Windows XP, running in Wine.

I would use kolourpaint but for whatever reason overlaid GUI elements like the selection box and brush cursors leave trails on the canvas.

Fun anecdote, paint.exe crashed the other day just as I was finishing up my drawing of the tower of Babel.

Windows 11 26H2 w/ MSPaint is 10.26100.1. It's just right.