Generated via ublue's countme script https://github.com/ublue-os/countme/blob/main/growth_global.svg
It works, but due to Flatpaks being quite isolated, you need to put put a proxy in between and adjust some settings.
I believe that this is the guide I followed: https://discussion.fedoraproject.org/t/how-to-run-firefox-and-keepassxc-in-a-flatpak-and-get-the-keepassxc-browser-add-on-to-work/19452