Mobo+RAM+PSU recommendations for a 24/7 computer

Hello hardware experts,

I'd like to ask for some advise following my previous question about cooling.

I want to build an efficient headless computing machine which will be working 24h/day with a pretty stable usage. Its purpose is distributed computing in a virtualized environment, big number of VMs with an average load on each VM. I will be adjusting an usage to avoid too much noise and heat. No overclocking. Undervolting if needed.

My choices so far:
+ CPU: i9-13900K
+ air cooling: Noctua NH-U12A
+ case: Corsair 4000D Airflow

What am I looking for?
* motherboard,
* RAM (128GB, I prefer DDR4), and
* PSU

Could you advice me the best parts for this build?

Thanks.