I appreciate this perspective and that was also my immediate reaction. Then I realized, as long as I can easily export my data and move elsewhere, I shouldn’t be too concerned.

For what it’s worth, there are some options on flathub.org even if they aren’t official.

I’m really happy with Fedora Workstation. I actually think Gnome is pretty great these days.

I wish I remembered more details but the consensus seemed to be to stick with Thunderbird. I use it every day and the new v115 really made it feel new again.