Been using it on my phone and browsers for maybe a year. Works great.
Browser plugin can be a bit shaky at times, but that might just be some side effect from my config of LibreWolf or something else.
I get your point. But Linux Mint does not have Snap by default, so that does not really apply.
I’d still recommend the normal Ubuntu based one since there is so much easily available help out there for any Ubuntu based system.
The Debian dist is (iirc) just there in case Ubuntu becomes unsuitable as an upstream in the future. I would treat it as a safe backup option, not a primary choice and def. not something I’d recommend to beginners.
But that’s just my take on it :)
Why tve Debian version? I’d recommend Linux Mint as well, but I’d recommend the normal one.
NixOS is exactly what you want.
You declare your configs in a way that you can just copy them to another computer and it willbe configured the same way.
I’ve never tried it my self, but I might for my next machine.