Help! My PC Keeps Shutting Off Randomly, Even After Replacing PSU and RAM

Hey everyone, I'm really at my wits' end and could use some help with a frustrating issue. My PC has been shutting down randomly, usually about once a day, sometimes even twice. This typically happens when I'm playing *Football Manager 2024*. Suddenly, the screen goes black, and the system powers off instantly, as if someone yanked the plug. There's no freezing or Blue Screen of Death—just an immediate shutdown. I did see an error message once, but it vanished too quickly for me to read.

Here's what I've tried:
- **PSU**: Replaced it with a brand-new one from the store, but it didn't help.
- **RAM**: Changed to **Crucial Pro DDR5 32GB (2x16GB) 6000 MHz CL36**, and the issue still persists.
- **GPU drivers**: I did a clean reinstall, but the problem remains.

Here are my specs:
- **CPU**: AMD Ryzen 5 7500F (6C/12T, 3.7–5.0 GHz)
- **GPU**: AMD Radeon RX 7900 GRE 16GB (XFX)
- **Motherboard**: Gigabyte A620M H (AM5, mATX)
- **RAM**: Crucial Pro DDR5 32GB (2x16GB) 6000 MHz CL36
- **Storage**: WD Blue SN580 1TB NVMe (PCIe 4.0)
- **PSU**: be quiet! System Power 10 650W (80+ Bronze)
- **Case**: Fractal Design Pop Air RGB
- **Cooling**: Stock AMD cooler (SQ-COOLER 03A)

As for temperatures, my CPU is often over 60°C at idle and frequently hits 80–90°C when gaming. I'm not overclocking anything, and the build is relatively new (from November 2023). The sudden shutdowns make me think it's not software-related. Could the CPU be throttling or triggering a thermal shutdown? Or is it a motherboard issue? Any help or suggestions would be massively appreciated! I'm open to running monitoring software or stress tests if needed. Thanks in advance!