Slackware current on btrfs for snapshots. Slackbuilds make the text go weeeeee, but the scripts will compile and build the package for you.
Plasma 6 hasn’t come over officially yet, but the main guy who put plasma together has a testing version out.
You could probably get the official proton app running, but I’m good with protonvpn-cli.
It’s been led by the same one dude since the early 90s. There’s nothing close to corporate about it. And there are great communities on IRC and matrix full of knowledgeable folks. And there’s linuxquestions.org too.