The cheesiness is part of the charm I'd say. Everything that is usually not shown or is implied in Japanese manga is exposed here.
She lays it really thick, as if it was an educational manga. Same-sex love, 101.
I appreciated how Ploy talked about whether Donut was ready to accept the realities of being in a same-sex relationship, and how Mew's conversation with her father went. They're very relatable topics. You're right in that we don't usually see Japanese manga go into as much detail in that regard, so it's nice to see even if it seems 'basic'.
Though I did find the dialogue to bit cheesy in Thai for the last few chapters, it was more... how they talked to each other rather than what they were saying itself, if that makes any sense. It's hard to explain. Might be a byproduct of going from reading 29 chapters in English to the last 3 in Thai.
For a seasoned manga reader, it's cringy. For first timers, it's cute. But after all, the target audience is Thai, so maybe not accustomed to yuri tropes and there, they like that kind of exposition.
Long story short, you're NOT the target audience. Sorry to burst your bubble.
There's a lot of translated BL and yuri manga in Thailand either through online scanlation or officially published Thai versions, so I don't think it's because we're behind or we're not used to yuri tropes. But "you're mine" is something I've heard couples here say so... could be more a cringy relationship thing.