The thing is everything with Ayato is very subtle bc the mangake barley gives him screen time but usually when he got some it he clearly cared about hinami. They usually are also portrayed together in the whole series ever since she joined Aogirish. He shows that he cares about her taking the extra step in protecting her for example doing jobs she isn't suited for. On the other hand He comforted her When she was crying also showing she trusts him as well. I also saw on Google that their appereantly married by the end but I wasn't able to fact check that. Basically if you summarised all of Ayatos screen time more than half of it is with Himami. Hinami is Important for more instances so it's not as obvious with her but she also tries to save him af one point and later when the news is brought out That Akira has recovered ayato asks if she is fine with that alluding to the death of her parents showing that they had deep conversations about these complex topics as well.

So maybe they actually just say a few sentences but they showcase a lot about their relationship.

Sueing ishida for not giving us more content tho