Why do you have "many" stock sales.  You can make one entry for each of the batches of covered short term sales and another for all the covered long term. If you have zillions of non-covered, do an entry that is explained by the attached pdf.

Maybe delete and start again?

https://proconnect.intuit.com/support/en-us/help-article/form-8949/entering-stock-transactions-form-...