For codes A & D (ST & LT basis reported to IRS) there should be no reason why the summary information can’t be used regardless of the wash sales. The IRS has all of this information.

The instructions for Form 8949 do not explicitly state you can’t use Various for the Sale Date. For many years I’ve used Various for the sale date and attached a PDF of the client’s 1099-B summary information without any complaints from the IRS so I don’t see why it can’t be done for 2020 other than the software won’t allow it.

I do notice you can put in an Adjustment Code M (Summary of multiple transactions on a single row 0- attach statement) and this will allow you to leave the Sales Date blank.

Would be nice if the powers that be (IRS/Intuit) could start making our lives easier for transactions that are reported to IRS