Why did you have it set to RST Premium? Are you using RAID? Are you using Optane? If not, don't enable it at all!
If you had it set to RST Premium when you installed Windows 10, then Windows 10 is no longer going to be able to boot when you set it back to AHCI. In this case, boot into Windows Safe Mode. Once loaded, you should be able to then shut down and subsequently boot properly.
Fast Startup in Windows power settings is not going to make a difference. I have it enabled and can still use scheduled power on.