Did the 1099INT show the whole gross amount? In what box? Only the interest should be in box 3. Do you have a breakdown from the bank for principal and interest? Yes only enter the interest in box 3. Subtract your cost from box 3. Did you get a separate 1099INT for the bonds or is your other bank interest also on the 1099 in box 1?
Oh, I assume you meant you cashed them in 2023 (not 2003)?