MSI mobo users have been complaining about this since the latest update to Windows. The problem is with the VBS (Windows 10 & 11 call it Memory Integrity) turning on. When enabled on their systems it causes the BIOS undervolt or overvolt to be ignore...
Just had this exact same issue. Clearing CMOS only worked if keeping the memory at 4800 MHz. Updating the bios did’t work either. So I removed the dimms. Moved dimm B2 over to A2 left dimm the original A2 off, cleared CMOS again and rebooted. It hung...