Windows won't shut down, instead restarts itself (not whole computer).

When I try to shutdown windows it instead restarts, and by that I don't mean that the computer restarts as if I hit "restart the computer" but instead of shutting down after the blue "logging off... etc" screen it just really quickly goes back to the desktop and starts up everything again (autostart, services) as If I had just started windows. It never goes to the PC Startup part where it lists the disks and RAM.
Restart works fine, like it should.
The problem started happening after I formatted and wiped one of my old drives which had a duplicate of my system drive on it (migrated the OS from that old HDD to my now new SSD).

Tried windows repair and sfc /scannow, says "everything is fine, no problems found".
I also don't get any relevant messages in the event log.

Any idea what could be wrong, what else I could check, how to fix this?

Can't find any download link for that, seems to be paid only?
I recently did method 1 of the following guide to fix some boot problems that I had ("you're PC needs to be repaired", which is now fixed) because I formatted another disk which also had Win10 on it.
After formatting that drive the shutdown problems started.
Fix UEFI Boot: Repair UEFI Boot in Windows 10/8/7 – EaseUS

I meant Macrium Reflect's Fix boot utility, somehow didn't read the part about partition wizard, oops sorry.
Anyway, thank you for the link :)
Just got a notification from windows "Reboot computer to fix disk problems" wtf...
What's going on
Guess it's better to wipe everything and start over...
I'm afraid of restarting now in case it won't start anymore, need to create a new bootable USB stick first.

I had that problem with a brand new laptop. I fixed it by disabling fast start in Control Panel power settings. Restart then run "powercfg /h off" from an admin command prompt. That disables hibernate mode and also frees up some disk space by removing the rather large hiberfile in the root of the system drive.