you ignore the 2022 k-1. your basis doesn't disappear because the k-1 for 2022 shows zero for beginning capital. that's because the partnership effectively terminated at midnight on12/31/2021. At that point there was no partnership so no beginning capital to report in 2022. the problem you have is the 1099-B. proceeds are correct but the broker never adjusts your tax basis for the partnership's activity, so it misrepresents The 1099-B would probably show what you originally paid which is wrong. by law the k-1s must now reflect tax basis and the last tax basis you have is from the 2021 ending capital so this is your correct tax basis for schedule D. to use what the broker reports as cost would likely result in you overreporting your loss, which if caught could lead to substantial penalties and interest. even worse if the overstatement of the loss is large enough there could be additional penalties.
