https://itch.io/jam/paint-jam-2020/topic/729141/is-mtpaint-also-okay is related
There is apparently MS Paint for XP on archive.org https://aur.archlinux.org/packages/mspaint-xp-bin/
It appears that jspaint can also be launched as an electron app:
git clone https://github.com/1j01/jspaint && cd jspaint && npm i && npm start
And there is also GNU Paint https://en.wikipedia.org/wiki/GNU_Paint