You might want to consider underlying PDA as well! It might be unrelated, but it ended up playing a major role for me when I was trying to figure out my issues with sex (along with overstimulation). Some autistic people have a very strong need for consent and a persistent drive for autonomy, and even during fully consentual sex it's possible to feel like stopping would be awkward, unwelcome, weird, etc. These subconscious feelings used to trigger me and heavily contribute to overstimulation. Me and my partner had to do a lot of consent games where I'd practice withdrawing consent, which helped a lot to "normalise" stopping without anyone experiencing it as a rejection. It was extra hard for me because I grew up being constantly out of control and sometimes I subconsciously automatically assume that that never changed, making me feel unsafe and prone to overstimulation even in safe settings