I don't do a ton of multi-monitor stuff with Windows these days, but I certainly have done a good bit of it. It worked OK on my desktop at home with three screens, and when I sometimes plug an extra monitor into my laptop at work it seems to put things back how they were last time.

But I don't recall a time when Bluetooth was "good" on Windows -- like, at all. I've spent somewhere in the realm of 20 years now dinking around with it. As far as I can tell, it has always been a miserable experience.