You need to figure out whether this is a memory or CPU issue. For starters make sure your windows is completely updated. I have a 14900kf too and I had instability on older windows versions that weren't fully updated.
Fully test your memory, memtest86 over night, tm5 w/ anta-extreme config, let run several hours, xmp disabled of course. Make sure your memory sticks are in a2/b2 slots of motherboard, not a1/b2. Make sure your bios is updated and chip set, Intel me, Intel me firmware and Intel serial io drivers are installed.
I'd suggest reseating your CPU and memory as well. Also make sure all of your PSU cables are gully inserted into the PSU (if modular) and the motherboard. If you're using a pcie GPU, reseat that as well. Test again.
Glad to hear you made some progress! Weird that reaching a certain power limit causes the system to crash though... Makes me wonder if your PSU is faulty if your temps are good. Honestly, it may also be worth checking the pins on your motherboard. Ensure none of the pins are bent.