I sign every message I send. I like that I can reasonably prove exactly what I did or did not write. Can’t remember encrypting any other than the occasional test message.
I gave up on Thunderbird with the release of 78. Previously Emigmail was just functional enough once I got its finicky settings all dialed in.
Now I’ve gone all in on [MailMate](https://freron.com/) on macOS. Out of the box PGP support was only one of many pleasantries I found when I first tried this a few weeks ago. It’s dramatically changed my idea of how well a GUI MUA can actually work. Money well spent!