"You cannot simply total the nondeductible contributions that you failed to report and treat that as an adjustment to your basis. "
If this what you are proposing to do on Line 2 of your next submitted Form 8606, you might get away with it if you are not audited by the IRS, (unlikely)
AND the IRS computers don't flag it as an inconsistency with prior Forms 8606. (likelyhood unknown).
Note that Form 8606 is not filed if you took no relevant action for 2024.
@dtubint
