I think it’s all but certain that they’d want user’s computers to to boot into something they made, or at the very least, slapped their branding all over, even if that was only a wrapper for their web browser.
Oh yeah, absolutely. They might even make Edge send some additional data to verify that it’s the browser being used. They might even add attestation with a binary is pinging Microsoft with messages signed by a microsoft private unique per machine and generated when the user signs in. They could add a paid subscription to limit the number of devices connecting to the cloud instance. For an extra fee they could add connection “from any device or browser”.
Or or or. There are a bunch of things they can do. They could also, as I said, just allow any browser to connect, but looking back, yeah, that’s probably naive.
Who knows and who knows how fast (or slow) governments would react.