If the computer boots but you can’t access a GUI, use Ctrl+Alt+F3 to open a console. From there you can use nano to edit the login manager configuration. If you had GNOME installed, your login manager is probably GDM, and its config should be at /etc/gdm/daemon.conf, according to the manual. If that is the case, it looks like you should erase the username under the entry “AutomaticLogin=”.
If I understand correctly, the filesystem driver is contained within the kernel for all linux-native filesystems (Ext4, XFS, BtrFS, F2FS, etc.), just as drivers for computer components and devices are. But drivers to access NTFS (Windows) and HFS+ (Mac OS) drives are programs in userspace
AFAIK, the port on your router is irrelevant as the VPN bypasses it. I’m not familiar with ProtonVPN, but with PIA you can get a forwarded port in the VPN app and specify that port in your P2P application. I use that method for Soulseek, but my qBittorrent works correctly in both directions without doing anything special.