I clicked on something to split my next year's tax payments into four, causing it to print with coupons (1040-ES) which I don't need and can't undo or get rid of.

Those four 1040ES vouchers are optional to use.   They are not for paying your 2024 tax due.  They are meant for making estimated quarterly payments for tax year 2025 to help you avoid a big tax bill and/or an underpayment penalty at tax time next year when you prepare and file your 2025 tax return.   You are not required to use them, and they have no impact at all on your 2024 tax return.

Thank you!