Recommend you do not file via snail mail. IRS was still processing paper returns from 2019 the last time I checked. If you're looking for a refund from a paper filed 2020 return, it could be a long wait.
I've also filed with TurboTax for a number of years, this was the first time my stock trades caused a hang up. And I didn't want to file an 88 page paper return.
The solution is to first clear out all your 1099-B trades. Delete them. Then start over again, filing of the summary of all the trades. The IRS accepts your summary as they already have each trade directly reported to them by the broker. You'll have enter any closed trades that were not reported, which is unlikely.
TurboTax has a procedure to do this, see my earlier post. My errors were cleared up and I eFiled as normal. Return was accepted by the IRS.
