Similar (though VERY slow moving) effort to do the same on my end.
My big hesitance is that I would need to centralize management (cause gods is it hard to get anyone to understand ssh), which says to me I’d need to have something public facing on my friends and family’s networks. That pu lic facing bit just makes me squeamish.
Haven’t used it in forever, but seems like Thunderbird’s was alright back in the day. I heard the project died, but then Mozilla brought it back? Not sure the deets on that.
But why moving away from Proton? Did they have a bad audit or something?