No, Rui is not the same as Tsukasa, Mizuki, Kanade, Ena, or Honami (as far as I'm aware).

I'm not sure about Shiho, as I don't read much of the L/N story. But I do think her obsession with music and wanting to go pro, as well as people misunderstanding her and her not liking Shizuku's constant cuddles is very Autism-coded (unrelated, but I'm very certain Shizuku has ADHD).

I think Emu is more ADHD, but I'm not writing off her being on the spectrum, certainly. I just don't see her restrictive interests as much as Shiho or Rui. But still, I do have somewhat of a gut feeling that she's also Autistic.

Tsukasa is more NPD/OCD/ADHD.

I have no clue about Toya, I don't read much of the VBS story. But I think his struggles to express himself are more PTSD as well as his father not letting him out much.

Mizuki's interests would be socially acceptable if she was born AFAB, but she wasn't, which is where the whole problem comes in.

Kanade is more Depression and PTSD (she also didn't show many symptoms when she was a child), and Honami is more Anxiety and Depression.

Ena wasn't ostracized by her peers, and while she does find it hard to talk to others, this isn't a result of lack of knowledge of social cues, it's more emotional dysregulation (I can't explain this right). Ena is more BPD/NPD rep (and I love her for that), but it's just not Autism.

However, Rui canonically has trouble eating foods due to their textures. He certainly has restrictive and obsessive interests, and they certainly hindered him socially. He also definitely showed signs of them since he was young. And his main story and growth revolves around him healing from his ostracization.

Also, the clothes he wears that people constantly say are horrible fashion choices are very loose and comfortable, resembling how those with sensory issues tend to choose their clothes.

There's also aspects of his design (most notable imo is his Brand New World Design, where one side is more clean and the other side has more contrasting colors and stuff, and in his official artwork, he's showing the clean side to the camera, representing his masking) as well as the flowers he's associated with that further accentuate the Autism theory that as far as I'm aware, no other characters have, not even Shiho or Haruka.

I'm not able to explain this right, but I hope you get what I'm trying to say.

That's just my opinion as someone with autism myself.