Then I got a phone call from an entirely different number that I didn't recognise and ignored... But which when googled turned out to be the AA.

So... Maybe Quest Worlds?

Or given the word vibe, perhaps Over The Edge

I think, given it's post technology, I would want a system that worked well for fantasy. (Also, there is something about the setting which gives me an Arthurian vibe). However, I would want the PCs to be displaced 21st century 'normals', so I wouldn't want a strict class system.

A fake sounding British accent never stopped Spike being a real character.

Also Putin said he attacked Ukraine because of all the Nazis there. Putin is Antifa!

Come off it: making his way in the world today took everything he had.