If I install software from .deb file, do I still get the updates & upgrades when I run sudo apt update / upgrade ? Or is flatpak the way to go? I’m not very familiar with flatpak, so I’m trying to avoid, but it seems that cons are limited. I’m currently running mint cinnamon (how original, I know), and asking because i can’t seem to add mullvad-vpn stable repo. Thank you for your help,
Generally, no. Apt gets its packages from the repositories, so unless (i) your .deb package gets added to those repositories, or (ii) you add a new repository that contains your package, it won’t be updated.