Taxes are a bitch and your story is even worse than the ones I heard over the years. I mean if I was forced to backtrack my log to when I first owned crypto and calculate all the profits/losses that would probably be impossible.

I know that many people use crypto tax calculator for this stuff so maybe that can help in the future.

I also don't want to alarm any regulators but if you ever need to slide something under the table Monero can be a good friend.