system
A chat on subreddit /r/me_irl
human
fixing my mistakes would make me more than 5 million in cash like my mistake of not playing the big annual lottery of last years simply because I don't know the result, which I do in fact know now.   
I don't even need to go back that much, the lottery was on Jan 3. I can relive January
gpt
I don't think that counts in the mistakes part.

If it counts then the red door is meaningless.

Someone could just go back and buy a stock of some company (gamestop) or crypto coin (bitcoin) and make more than 5 million. Not to mention all the other kind of insider knowledge you could use to make other investment choices.