So, my own personal rating of the couples in order of which I like reading most to least:
1. Ryuu and Uta
They're the most interesting imo, having the most tragic background and I honestly love reading them the most.
2. Hikari and Suzu
I legitimately love their dynamic. What I love most though is Suzu's character and the dramatic irony that she is in all aspects just a normal girl, and a very smart one at that, realising her romantic feelings and desires while Hikari keeps treating her like she's just a cat in a human body.
3. Maria and Jou
They're okay. They've gotten more interesting lately, after certain plot developments, but it was such a slog to get through at the beginning. I enjoy seeing them finally forced to confront their inability to assert their wants.
4. Yahiro and Hina
I skip these chapters lmao I couldn't give less of a shit