In the diagnostic criteria for ASD in the DSM 5, eating the same foods every day is specifically listed as a symptom and matches up with what you’re describing. Not every autistic person has the same sensitivities, and some people on the spectrum are even sensory seeking and may enjoy things that would drive another person on the spectrum up the wall.
Keep in mind as well a lot of the descriptions of autistic behavior are focused on children, who are less able to mask than adults. So think about how you would have reacted to being presented with new foods at like 5-8 years old, not necessarily now.
And informally I would say that overthinking the hell out of the diagnostic criteria should itself count as a symptom, haha.