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.

It's listed as "medium difficulty" due to newer hardware in the laptop not being fully compatible with the kernel shipped in that old version of Ubuntu. I believe 22.04 is compatible out of the box.

I had to use a Debian sid nightly installer to set up Debian on my laptop, no big deal for me but for someone new to Linux I can see why that might be off-putting.