In 2020, events that showed the worthlessness of the stock were, in my opinion: Delisting of the shares from trading No bid/ask anywhere Valuation by brokerage account as zero Deregistration of the stock by the SEC (Registration Revocation order) Lapse of the Corporation in Delaware
I think that no one would have a problem proving these things happened. But if you say the stock went worthless in 2021, I think you have a problem.
Also, I can amend my 2020 tax return if TMPS starts trading again, within a time limit. But right now the shares are still worthless and I suspect that 2020 will end up being the last point in time that the shares weren't worthless.