I’m not a Mint user but I would assume the Ubuntu/Debian install instructions on Mullvad would work on Mint as well
~~https://mullvad.net/en/download/vpn/linux~~
My bad, just read further in mullvads documentation and they do state that Mint requires manual installation. If I understand it correctly you will need to follow these instructions to install updates as well.
https://mullvad.net/en/help/install-mullvad-app-linux#install-manual
Way back: Ubuntu live CD. More recent history: Pop!_OS > Zorin OS > Fedora.
Happily been running Fedora for like 2 years now.
Fedora because it’s boring in the best ways. Curious about NixOS though.
Mullvad + Transmission
Haven’t heard of Lingmo but I’d say the same ui style is achievable in any OS using gnome with theme and dash to dock.
Go for something like Debian or Fedora and theme it.