you can use specific identification. However, you must identify the shares to be sold before they are sold. I'm assuming you didn't use this method for shares sold so far in 2020. some brokers will accept standing orders to use S I but then on every sale you must identify the lots.
here's from IRB 2010-47
The final regulations retain the requirement for written confirmation of all sales and transfers of specifically identified stock as a reasonable safeguard that specific identification orders are properly executed. However, in response to these comments, the final regulations provide that account statements or other documents a broker or agent periodically provides to a taxpayer may serve as written confirmation if provided to the taxpayer within a reasonable time after the sale or transfer.
