For an inherited IRA with basis, the names on 8606 should be "<owner> and <your name> BENE" or Beneficiary if it fits, and your SSN.
TurboTax won't let you enter that name,
You'll have to file on paper anyway so get the form in fillable PDF from IRS
TurboTax will calculate the taxable part if you pretend the IRA is your own IRA with basis
OR
Just leave prior years and start with the original basis on 2025 tax return.
You still have the 8606 name: issue.
reply back if you want a workaround for that.
@frankharry
