The portrayal of autism in heated rivaly is perfect, because the entire bar scene at the all stars game is Ilya trying to find out more about how serious it is with Shane and Rose, with three covert attempts, while Shane notices nothing of that and just talks happily about his parents and his stylist, until Ilya realises that he will not get this information without asking Shane directly, so he finally does. He was so sure he would get his heart broken by Shanes response to the clothes question, put up a brave face for it, and then got hit unexpectedly with Shanes dorky answer that made him have a real smile.
My boy Shane did Not realise any of that.
And lets be clear that this doesnt equate to Shane not having secret motivations during their conversation. He feels a bit bolder, a bit braver, because of his coming out talk with Rose. He told her he wants to figure some things out. He is also giddy and elated to be able to talk to Ilya openly, in public. He is trying to make hopefully inconspicuous conversation, and also so happy to see Ilya. He doesnt even really care what they talk about.
And again he is fully not noticing what Ilya is trying to do. One might say its because he is busy with his own emotions, and he definitely is, but closeted controlling Shane Hollander is definitely dedicating a bunch of brainspace to how their conversation is perceived from the outside the whole time.
Shane does this a lot, honestly, just being so happy and relaxed in Ilyas presence that he goes on about banal stuff and every day life and his parents and stuff without noticing what kinds of wars are waging inside Ilya, because he is autistic, and because Ilya hides it.
Ilya is aware of this trait of Shane's, i am certain of that, and on many many instances he works extremely hard to not trip Shane up in his flow, and to not let Shane see things he doesnt want him to see and doesnt want to talk about (for fear of emotional inimacy and other reasons), for example during the tuna melt metup. I think Ilya is extremely aware and good at this social stuff. He might not care a lot of the time, and he anjoys his asshole persona and other times is also like "i literally dont have time for this, i am under severe stress already". But for Shane he does care, even if he doesnt want to but Shane needs him to like in the coming out scene.
Also, angsty note, while i think that Ilya has a natural predisposition, i also think that his very unsafe and oppressive environment at home pushed him to put a lot of energy and skill points into his social skills. already in general, and then the high risk secret of his bisexuality added pressure on top.