Thunderbird would benefit greatly from better signature management. I need different signatures for one email address, and this isn't possible with the built-in features or plugins. None of them work well. Furthermore, users should be able to create and, more importantly, format signatures without relying on external tools that first generate an HTML file.
This all feels like it's in its infancy, as if Thunderbird were still under development, certainly not version 147.02. I don't understand why no one has needed this feature before, which has been available in Outlook for decades.
I finally want to get away from Outlook.