1040-ES for 2025 were stamped with "DO NOT FILE". How do I print copies without the stamp?

you'll have to wait until they're finalized. the first estimate is not due until 4/15/2025. an alternative is to use the IRS website and register for direct pay. no lost in the mail tax payments and you can print out a confirmation about the payment. sometimes the iRS will take it out late but as long as the date you specified was on or before the due date and there were funds in your account, there will be no penalties.

https://www.irs.gov/payments