I don't think that there is any benefit to waiting to file your 2025 tax return. I have never seen any evidence that the IRS tracks your IRA basis or compares Forms 8606 between years outside of an audit, instead relying on the taxpayer to provide accurate information on an individual Form 8606. As long as your 2025 From 8606 is accurate relative to the amendments for 2023 and 2024, that should be sufficient.
