Firstly thanks for the comments. Well received and interesting all of them.
Quite frankly I'm going to look like a dick here.
I just put £1000 on the table for an experiment and trialled over nearly a month and it went as follows:
Firstly I bought a Lenovo Neo 50s workstation, a relatively meaty in perspective Intel i5-12400 and upgraded it with 32GB of RAM and a 1TB Samsung 980 Pro SSD. This is a mid-range current line desktop. This was plugged into my spare Iiyama 27" 4k monitor, Durgod K320 keyboard and reused the MX Master 3 I use with my Mac. I installed a fresh windows 11 64-bit install (not Lenovo crapware stuffed). Network was hard wired 1Gb ethernet to my router.
The good
1. Honestly it's pretty damn fast. It feels slightly more responsive than my M1 Pro MBP.
2. Virtualisation works pretty well. No issues there. I had a whole Kubernetes cluster running on it in the first afternoon.
3. Cheap. So so so so so cheap for what you get. I can't complain there at all. Even the O365 sub at £5.99 a month for personal with 1TB storage is crazy cheap.
4. It was nice to see some things in actual files rather than opaque containers.
The bad
1. Windows 11 is just absolutely ****ing horrible. I spent the first day battling with getting Windows 11 settings and privacy and generally getting it to stop bugging me every 5 minutes about something or other. Since then it's a constant stream of difficult to reproduce things I've had to do to it to stop it annoying me in some new way.
2. Power. This thing will quite happily suck 80W doing what my M1 uses about 20W for.
3. Microsoft's cloud stuff is garbage. The whole O365 and cloud sync stuff built into the OS is absolutely dire. It's unreliable. Within 3 hours of me doing something I'd managed to irreparably corrupt a OneNote notebook. I'm not even starting on OneDrive which has some serious consistency issues with syncing a mere 20Gb of files.
4. Sorry but absolutely nothing even touches the Studio Display. Side by side with the Iiyama which is 99% sRGB and I did colour cal on, it doesn't even compare. It's horrible. Add the Windows 11 HiDPI problems and required 150% scaling blurriness and it's obvious that the Studio Display is more than worth the money. You plug it in, it works and it looks bloody amazing. That's what you're paying for.
5. There is absolutely no competition for the stuff built into macOS. Mail/Calendar/Contacts/Notes/Reminders/Apple Music/Numbers/Maps/iMessage/Safari/Photos are nothing special independently but together they are absolutely amazingly good tools.
6. Microsoft have just discontinued custom domain support for outlook.com unless you fish out money for O365 business which is $$$. This is effectively free with anything but the basic iCloud sub.
7. There is no replacement for Apple Photos and Apple Music that works across iOS and windows. It just doesn't exist. There is nothing. I spend days looking. Spotify is not it for reference! Neither is Lightroom!
Conclusions
1. It's mostly bad on the windows side of the fence. I'm solving the virtualisation gap by renting cloud instances now and doing work on there. If you shut them down when you're using them it costs < $30 a month and there's no hardware around to depreciate.
2. You get what you pay for. I'm paying for Apple and I'm perhaps happier now I've tested this.
3. I probably look like a dick based on my first post but I am a big proponent of owning up to your mistakes. I will wear the dunce hat and sit in the corner and reflect.
4. I burned £1000 on this experiment. I will get perhaps £800 back when I bounce all the crap on eBay. So the total cost of this thread is £200. Please enjoy watching me pissing cash out of the window to hurt myself for no good reason.
As a side note I have sold my iPad Pro because it turns out it's mostly an ornament. The MBP and the iPhone do 95% of the work and the rest does not justify the cost. I will miss it for digital art but I hit cultpens.com and bought some toys to play with on paper for a change. Display is also faster than 120Hz