For Windows 10 & 11, and KDE Plasma 5 & 6 (Wayland only).
flatpak --user remote-add flyingpie https://flatpak.flyingpie.nl/index.flatpakrepo
flatpak --user install nl.flyingpie.wtqflatpak remote-add flyingpie https://flatpak.flyingpie.nl/index.flatpakrepo
flatpak install nl.flyingpie.wtq