Have you ever disclosed to the interviewer you stutter? It works for me so you don’t need to force yourself to be a fluent speaker that you can be confident and a stutterer at the same time but the right person will see you for your confidence and the right qualifications and skills you can bring to the table. This way the interviewer won’t assume your stutter is due to you being incompetent, confused or anxious that it’s way more complex than that!