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.
I’m from feddit.nu, the swedish instance. Or at least one of them, there might be more swedish instances I am not aware of. I like it because I can find local content and post in swedish.
I think everyone should aim to find a smaller instance where they feel like they belong to and create their account there.
There’s no reason to have a federated system if everyone uses the same 3 large instances.