display graphics drivers comes baked into the kernel, you don't need to install anything, they are already there. messing with them is a bad time if you don't yet know what you are doing.

first things first take a look at your system logs to see what went wrong. depending on your installed vpn you should be able to just apt purge it.

As far as reinstalling and losing your data, you may want to just backup /home to a USB disk now.

You'll want to figure out the VPN issue, so maybe post what you know about that. Also post ifconfig -a or ip addr show. Also the output of route for good measure. Can you ping anything? Is it just a nameserver issue (try pinging 8.8.8.8 and kernel.org, for instance)?

Once you have network access, I'd install tmux if you're going to be spending any significant time debugging in the terminal :)

You should be able to use nmtui tool in the text terminal to activate your network connection. From the terminal you can also use the startx command to try and see if that would show you a GUI or other useful errors.

If secureboot is enabled try disabling it. If disabling secureboot resolves the issue re-enable secureboot and add the dkms signing key with mokutil: https://wiki.debian.org/SecureBoot#Making_DKMS_modules_signing_by_DKMS_signing_key_usable_with_the_secure_boot

the apt logs probably contain the versions you had before that. you could try and go back.

in any case: make backups before updates to prevent this in the future. even an incomplete backup can be better than none.