Perhaps you could share a video that explains some of the things you’re trying to communicate? Or perhaps writing it down in text or some other format may be easier. And make sure to say its not because you don’t enjoy spending time with him its just that you can’t always do certain things. For me when i’m overwhelmed and don’t feel able to talk i find it better to be asked yes or no questions or things that don’t require much thought, you may be different but it might be worth telling him that if you’re the same. Hope he understands, i’ve been through this and know how frustrating it can be to feel misunderstood.

My ex was like this. He's a complete sweetheart but he couldn't fundamentally get it and it ultimately caused communication issues. I didn't know how to verbalize my needs then, so now that would definitely be helpful. If this relationship is good for you and you care for this person, it may be worth working through. For me, the attempts at fixing it didn't work and it became too much. It didn't mean either of us were bad partners, just had conflicting wants and needs. I have decided to (try to) only date others on the spectrum/neurodivergent ppl going forward. Feel free to message me :)