[2022] How do you I prove that my computer is crashing, so that i don't get time penalty

The system for DC's can only tell that you left the game - it does not disconcern whether you left because of a PC crash or a ragequit as the result is the same, the match is still ruined for the other players in that match.

I would suggest looking for technical assistance to assess your PC to attempt to find out the cause of your crashing.