I use it as well, and it's a turd of a program. However, the flipside is that nowadays, with AI, one can build addons very easily, to fill missing functionality.

It’s a turd of a program today, but it didn’t use to be. I bet that if you took one of the earliest versions from 20 years ago and fixed the security issues, you’d get a great email client, because that’s what Thunderbird once was and email itself has barely changed.