Is there a big difference in the updated versions? Should I uninstall the deb based Geary that is preinstalled and use the flatpak?
Edit: I installed the v44 flatpak and gave it a try. Maybe it was because I already had Geary installed, but it was mega buggy. However, v44 has some good improvements and one of the main ones for me is that they suspend the email engine when you suspend the phone. This means that when you resume it will be aware of things and not stuck on some previous operation that was underway when you suspended.
Some more testing from the community here would be good. I would like to use the more current version but will wait until there is some good feedback on that.