We used to run firewalls running Fedora at work, works fine. Issue is you’re only getting 6 months of updates, best to look at Rocky Linux for something that doesn’t change much if you do anything beyond a single program.

Previous blogs have mentioned K-9 is just being rebranded as Thunderbird for Android once the Android app is closer in features to the desktop release. The iOS release will be new entirely as I don’t know of an existing iOS email app they can rebrand.