I am having this issue ever since after I switched from Intel to AMD CPU recently (back to AMD after 8 years !).
In Windows 10, after each reboot, power plan switches itself to AMD Ryzen Balanced (from previously selected AMD Ryzen High Performance, which I prefer) and its settings are being reset to their default values too (especially, "Go to sleep after" switches from my preferred Never to default 2 hours).
How can I prevent this ?
You can try and reset things by opening Windows Powershell (Admin) and running "powercfg -restoredefaultschemes"
Then re-install the latest chipset drivers
This may break any weird power settings that may inflicting your system
After a lenghty research, I eventually found the culprit. It was ASUS AISuite 3 that was resetting power plan (and my customizations made to it) back to 'AMD Ryzen Balanced' after each reboot. Once I disabled automatic startup of AI Suite 3, the problem went away, it is staying at 'AMD Ryzen High Performance' now.