That could be done after the user enters both the email/username and password
Edit: sorry, I think I misunderstood what you said, but if someone is using something like "sign in with google", we've had separate buttons for that for ages.
I now have two gpus, but I've run single gpu passthrough for a long time without any issues. However, you have to keep in mind that some software (such as anticheat for games) will refuse to run in a virtual machine.
IMHO arch is way too overrated. It does include a lot of stuff in the repos that others don't have, but the benefit end there in my opinion. My experience on fedora has been way better.
How would I use that in this situation? I don't get it. I already have a vpn set up to communicate between the two devices, and have been successfully running multiple services in this configuration for about a month. It's just XMPP that I'm having trouble with.
There is some obscure/proprietary hardware that doesn't play nicely with linux. Fingerprint readers may not work on laptops, for example. I've had trouble with a trackpad in the past.
I use a self-hosted vpn, because I don't want to expose anything to the internet. The ones I do want to, I haven't set up yet since it would require reinstalling my pi. But I do have a reverse proxy set up on a vps that I will use once I get around to doing it.
As long as you are okay with using the web versions of office, you can basically go with any distro, since all of them have at least a web browser and virtualbox in their repositories, as well as vs code. Jetbrains also works (I've only used intellij but I assume the others are just as easy to set up). I've never tried visual studio on linux though, not sure how well that works.
I would take the toaster one just so I could mess with my friends