Day one edition Xbox started to crash constantly. Rendering games doesn't happen if it...

yes did that

the same thing happened with my One running Fallout 4, it has started crashing like that one day on constantly, like maximum 2h of playing

Hello

It could be old age. Things wear out as time goes on. If it's the Original Xbox it's not covered under any warranty. You could send it in for repair but it may be the same price as purchasing a new one. There's lot of great deals happening these days. It
may be worthwhile looking into.

Try performing a hard reset EXACTLY like this. Hold the power button on the console for 8 seconds or until the power shuts down completely.
Unplug the power cord from the back of the console for 5 minutes.
Plug the power cord back in and restart the console.

Try a different hard drive. I had external hard drive that was doing something similar to your symptoms. Hope that help.

I just bought it new a month ago. I clean vents out regularly (Had an original XBox One, prone to overheating so I learned my lesson)