It may be worth talking to a specialised PC shop, you may also need to check your house electrics will support that kind of setup. You may need an electrocution to come in to do some work for you.

https://www.pugetsystems.com/labs/articles/1-7x-nvidia-geforce-rtx-4090-gpu-scaling/

Puget has some info on power use that may be of interest, that link is for 1-7 RTX 4090's scaling. They may also be worth talking to if you want some one to make your setup for you.