[OnePlus 6 ROMs, Kernels, Recoveries, & Other Devel] espionage724:
I finally went and got this set-up, I used Windows 10 21H2 LTSC. It went smoothly and I was playing classic WoW from Battle.net surprisingly fine at 50-60 FPS and decent settings.

Edit:

DO NOT

install the "Qualcomm Technolgies, Incorporated - SYSTEM - 7/1/2009 1.0.105.40.0" optional update in Windows Update as this causes repeated BSOD and/or Crashdumps on Windows boots. Removing the driver was easy with dism and doing the USB UAS mode thing. It's either qcwlan850.inf or qcsubsys850.inf. After removing that newer Wifi driver and letting Windows use the older built-in one, Windows boots fine again!

There's nothing for phone calls/texts by-default in Windows 10 LTSC, and seemingly nothing in Microsoft Store. I have no idea what's available to do calls and/or SMS on desktop Windows and imagine this isn't too-common.

I had to manually add an APN I think, but LTE data was fine (Tracfone US with T-Mobile SIM; Windows showed T-Mobile LTE)

Even though dxdiag reports DX11, classic WoW ran by-default with DX12 and works well until a specific in-game setting was changed; both DX11 modes were fine

Battle.net client installed no problem; KeePassXC needed an older version for win32

Changing any Wireless card driver settings for the Qualcomm/built-in card or causing the driver to reload for it seemingly causes a Crashdump

No built-in speaker nor 3.5mm audio; Bluetooth speaker worked fine

When choosing the userdata size, I did 8GB for Android which booted LineageOS 21. A fresh install of LOS21 without Google apps uses 15GB so I recommend setting userdata for Android to something like 19GB or higher

I was able to Msmdownloadtool restore and get back to LOS21 after Renegade Project no problem

Wifi was 866/866 (same as reported in Android)

Battle.net client is win32 but installs and works fine; classic WoW when restored from win64 backup updated fine and switched to ARM64, which also worked fine (was concerned about a note on GitHub about ARM64 graphics not working)

Charging through USB passthrough from a C dock was reported to work from Windows, but I had like 40% battery when I booted back to Android when finished implying that it either slow charged or didn't at all; this was probably the hardest I ran my phone's hardware and it was hot

I used a USB 3.0 USB-C dock, 130W USB-PD C laptop charger on the dock, generic USB keyboard, mouse with 2.4GHz dongle, and a relatively generic Bluetooth speaker

I didn't need dism++ nor gdisk. I used step 2.1 for Mass Storage Mode, and installed drivers via dism. All mentioned partition numbers were different for me. boot needed flashed if you want to always boot to Windows (can still boot TWRP and LOS recovery manually later or reflash them)

EDL nor bootloader/fastboot reboot modes worked for me from the UEFI bootloader menu; had to disconnect USB and use physical buttons for fastboot

The win32 emulation mode (just running win32 apps as-is) worked fine on Windows 10 LTSC 21H2 IOT ARM64 (some websites say that it's only for Windows 11)

Didn't test camera, GPS, or microphone (there's no audio output driver so presumably no mic/input on 3.5mm, but may be fine through BT or USB)

Overall it was pretty cool, but not for daily real-phone use. It was cool being able to play WoW! I don't know if the phone's wifi is unstable when it's connected, but if it is I'd recommend USB Ethernet or wifi. I have an (untested) USB-C dock that has Ethernet, 3.5mm audio, and some USB ports that would be perfect for this kind of set-up! I saw a video of someone else doing this with a OnePlus 7 and side-controller mounts that looked pretty fun!