Wait why Gustavo? I think he's just masking as an oppressed gay (like all oppressed minorities do even if homosexuality doesn't hugely affect his behavior), but I would be happy to get more insight. To clarify, I watched Beter call saul and around 3 seasons of BB.
His unemotionality. The way he speaks formally. His precise mannerisms. The way he always seems to be putting on a facade, like he's an alien pretending to be human.
I don't think he was intended to come across as autistic, he just vaguely seems like it.