There is no IRA/SEP/SIMPLE box on 1099-R

Then you don't check it  What is the 1099R?  A 401K or pension?  

If the Form 1099-R you received from the plan administrator does not have an IRA/SEP/SIMPLE box then you do not check the IRA/SEP/SIMPLE box on the TurboTax Form 1099-R.

IRS Form 1099-R (2021) - https://www.irs.gov/pub/irs-prior/f1099r--2021.pdf