I tried it on Lacerte.  It took multiple transactions (5) up to 2,000,100,000 of proceeds then it started to mess up the Gross proceeds.  The basis (under $2B) was okay.   The gain was okay.  all the individual transactions flowed to 8949 okay, even the gross was correct, but the totals on 8949 started to mess up at about $2.1B

I checked my old file, The transaction was for $1.2B.  It was okay back then.   It took two line items.

Because the net was correct, if I had this problem today, I would paper file it and type up the 8949 and Sch D.  It's no fun when the client gets the CP-whatever love letter and has to pay me to draft the Dear IRS letter.  I would ask the client to decide.