That's why there's a huge miscommunication between the audience and original text. People tend to forget the culture of where this originates from. Also doesn't help that there's no equal equivalency in gravitas when it comes to word/phrase choice.
There's also the underlying tension in the story where Yuuma has more to lose if he outed himself and Ryohei knows that. Yuuma somehow feels like he's on the edge in the relationship but Ryohei is more than ready to catch him if some shit happens.
Time will tell what comes out of this relationship but I don't agree with the assumption that Ryohei puts less into it. I'd be willing to read more but I hope if the author decides to continue, let it not introduce a 2nd ML. Love triangles are just not that interesting to me.
Equal equivalency??? Lol whut
"ryohei doesn't love yuuma that much etc etc blah blah"
yet he's the first in the relationship to say 'aishiteru' which bears more emotional significance than 'daisuki'. it's rarely ever used in proclamations of love because it's typically reserved for serious relationships and portrays the complexity and depth of love eg. hjgh school couple won't use aishiteru. a couple that has been married and in love for 15 years will...it's not used lackadaisically. that's why yuuma even gets shocked that ryohei said it before he(yuuma) did because yuuma thoughe he bore "more love" for ryohei than ryohei did for him.
you may have qualms about yuuma's characterisation and i can see your point (he's bland boring etc) but i deny the implications that ryohei doesn't love yuuma yet he's been unabashedly vocal & communicative about it.
maybe you just lack the ability to critically view ryohei with depth and are stuck to his pre-developed playboy characterisation from likr ch.2 of the prequel. take a break and come back and re-read it later in the future maybe your opinion will change.