Can’t boot PC after upgrading CPU

original pc was

i7 12700k

ASUS TUF Z690 plus D4

32GB DDR4 RAM @3200MHz

RTX 3060 Ti

750W beQuiet PSU

I attempted to upgrade my cpu to i9 14900kf and the initial boot failed - there was no POST. For context I originally had an older BIOS version (2302) which didn’t yet support this cpu, first BIOS that started supporting it was 2602, so I straight ahead updated to the latest 4505 BIOS and made all settings default while I still had the original configuration with the i7 cpu. Once I built it fully (and yes all the connections were 100% proper, well connected cables, properly mounted cooling, fans, correctly applied thermal paste, etc) the boot failed, all the case fans would spin for half a second and stop, but the gpu fan, cpu cooler fan kept spinning and the monitor didn’t receive any signal. I tried everything like resetting the CMOS, eliminating the GPU temporarily to see if the power supply was fine enough for the CPU, remounting the RAM and assuring notning is loose, and none of that was successful. Out of frustration I put back in the old CPU and it worked flawlessly, no boot issues. I sent back the new CPU thinking there was something off with it but they confirmed it works, they tested it on some b760 board idk exactly which one. Am i missing something, what could possibly be the cause(s) for my issue? the BIOS displays the version is 4505 so I suspect its fine but im still assuming something is off with it, some guy in tech support swears by having to update the BIOS first to the initial version that started supporting it and then to the latest after but that made no sense to me since the updates are cumulative as stated by ASUS.