Microsoft has you covered, they sell a thin client box that has enough OS to reach the internet and use their browser and office swuite online.

https://www.microsoft.com/en-us/windows-365/link

Yup.

I mean, there's the slightly slower model for £500 but you know, that's actually worth ~£200 or below

It's monstrous, even that A-tech.. :( I hate to imagine the corps sucking them up buying them in bulk at about 80% off.. But they can afford it. The only ones losing are us, either buying them at this price, or the sellers, forced to dissuade the public from buying any because Daddy Meta wants it all