Best advice ever, buy better 1000W PSU, those spikes of power usage might burn your PSU and leak power to any low voltage lines. It is extremely dangerous for motherboard and ssd/hdd to get power spikes due to insufficient power supply. Most probably you have some low grade PSU, but anyhow any good PSU gold/platinum 1000w would be best option for you friend.

No OC case 22k multi and 1900 single, oc 24-24.5k multi, 2-2.2k single. All numbers cb r23.

I have 192GB 4 sticks 6400mt/s, running @5200mt/s with z790 and 13600k, so 14900k should run with good memory with 192GB with 5200mt/s.