I agree. the mangaka made Takeo's feelings too subtle. She showed hints of it - his annoyance when others intruded on their lunch, when another guy gave him his scarf and gloves, when (in the final scene) he saw someone talking to Takeo. It was too focused on Wako's POV and insecurities but his insecurities were valid and they never really addressed that - Takeo basically said just trust me but that's not how trust works, it takes a lot to make that leap and in the end, Wako did it but to the readers? Takeo is simply too ladeedah about everything - there was no serious pondering, there was only tiny hints of jealousy, etc.
It felt mismatched - Wako seems to be a lot more in love than Takeo. But, like you, i don't think that is the case - I just simply think that Wako's situation makes it that Takeo never feels things like jealousy or possessiveness - wako is sickly, he's reserved and physically keeps a distance, girls don't really fawn over him. On the other hand Takeo seems to attract a lot of attention, which can cause insecurities. I think the mangaka should have had a had a scene where Takeo became upset (even if it was a misunderstanding) and experienced some of Wako's feelings so that they were on a bit more of a level footing.
This is an Overprotective Bf X Overthinker Bf typa relationship and this manga SERIOUSLY NEED VOL. 2 because we need Takeo's pov badly.... and it seems i think a lot of people in the comments misunderstood his character.
Well this is just my imo but first of all regarding in the main story with Ao, I really do think Takeo's feeling for him wasn't romantic at all. He's naturally a caring guy which we can see that here, how he takes care of Wako because he's "weak"(body) and I think he saw Ao in his "weak" state that it trigger something in him that he needed someone to help him or protect him. It just happens that he got involved in the main couple's misunderstanding that it made him think that it's actually possible to fall in love with the same sex too.
As for Takeo's feeling for Wako.... sadly we didn't see his pov, ugh!(this could have been perfect) we can only see his subtle reactions and actions but I think he genuinely did fall in love or also inlove the whole time with Wako(they just both don't know lol),,, like him getting jealous when someone trying putting scarf thing.
We only see Wako's pov in this story and him being a super duper overthinker doubtful with Takeo feelings.. made a lot readers doubtful too i guess...
But the thing is i couldn't blame him at all since he already made a resolution that he's always gonna be the "best friend" for his "straight best friend" for the rest of their lives!