If it could take 2 or more weeks for Windows 11 to blue screen, that is likely a Windows 11 issue (drivers likely).

If you boot and run the system from a live Linux flash drive, and it runs fine for 3 weeks, you can probably eliminate a hardware issue. If an extended memory test passed, the hardware is probably OK. Memory would be the first hardware item to swap out if testing hardware.

What video card, if any, are you using, or are you using the video adapter on the motherboard? What system make and model, or motherboard make and model do you have?

Linux Mint with the Cinnamon desktop would be an easy system to use. It should have a built-in web browser and office suite that might be able to get you through several weeks of testing.