Question for women: Does telling a guy "I didn't feel a spark/chemistry" after a first date mean exactly that or is it a diplomatic way of letting someone down gently?

Context: I've had 4 dates in the last 3 weeks all via the relatively new app Breeze. In my mind, I always end up feeling as if they went well but of course you would wouldn't you. But reality is different as all 4 have said variations of the same thing "I had a good time, you're really lovely but I didn't feel a spark". Naturally there's disappointment, but also confusion at the vagueness of the message. Like what was missing? Did I do something wrong? Do I not have much life experience?

I have ADHD as well as being autistic. I've never said to any of my recent dates about being Autistic but I have ended up revealing about my ADHD never intending to but it just happens in conversation, and it's often in a very self concious way because I'm always scared about being judged or disliked or that it could be a red flag because of the stereotypes and how too many men with either or both end up being vile misogynistic you know what's beginning with i.

But putting that can of worms to the side, I recently learned a psychological term called Limerence, where you become infatuated with someone infatuated with someone instantly despite the other person not feeling the same way. That probably has some ties to Rejection Sensitivity Dysphoria which I know I feel strongly. It could also be related to misreading social cues, not knowing when things are going well or not.

I know also, right from when I was a child that a lot of the things I'm into aren't relatable to a lot of people, maybe that's the lack of spark they meant. Because with any new job, new school setting I really didn't gel instantly and did need a little more time to adapt which idk a lot of people haven't really got that level of patience, they just want the now (myself included, I am kind of a dopamine fiend in certain aspects of my life)

It does feel like trying to find a job in the current market. I think the apps have a role in that. Where you know how you apply for numerous jobs but you're lucky to be invited to an interview once every blue moon if even that but the only real way to get on the ladder is if you know someone there already and they can put in a good word for you (even in retail its like that). Does this also work for dating, have you ever found a partner through them being mutuals of close friends of yours? Or is that a bit of a sitcom myth?

Would you ever tell a guy the exact reasons, or is it a bit Jack Nicholson "you can't handle the truth"? I'm sure there a lot of dudes that aren't worth that kind of hassle cause they're just assholes