Weird PC problems

So I had this PC that would crash in most games I'd play (BO6, Fortnite, Garden Warfare 2, Space Marine 2) even had an issue where If I hit the floor, my pc would restart so I took it to a PC shop and that issue was fixed with a new powerboard.

They tested games for hours with all my things plugged in and zero crashes. I even played Fortnite in 4k at the shop for 2 hours and had no problems. So we decided that my house just has problems with the electricity at home becasue I only had problems at home.

Specs:

-Ryzen 5 3600

-3060ti

-Corsair Vengeance Pro 32GB Kit DDR4-3200 C16

-B550M DS3H

-1TB M.2 [NVMe] SSD

-MPG A750GF Power Supply

-Windows 11

3 years after first getting the PC, I ended up getting a new PC

New PC specs:

-Ryzen 5 7500F

-ASUS TUF Gaming B650M-E WiFi DDR5 AM5 Micro-ATX

-Gigabyte Radeon RX 7800 XT GAMING OC 16GB

-Predator Vesta II RGB 32GB (2x 16GB) DDR5 6000MHz CL32

-Team MP44L 2TB PCIe 4.0 NVMe M.2 2280 SSD

-XPG Core Reactor II 750W 80+ Gold Gen 5 ATX 3.0 Fully Modular Power Supply

-Windows 11

I have had this new PC for 3 weeks and it works flawlessly with maxed out settings on the games that would crash a lot. I gave my Old pc to my friend and he's having crashes on Neon white and extreme crashes on Marvel Rivals. So now that I know that I can run a higher spec machine in my house, what the hell could be going on with my old PC? I have been thinking of getting him another Power Supply or Ram. I would love to get another eye on this though thank you for reading! :)