The main love interest in 'My Best Friend Doesn't Pay Attention to Me' is Shima Itsuki. This is one of those cases where the title is super literal—the childhood friend and apparent 'best friend,' Itsuki, is so focused on the heroine, Iori, that he doesn't even seem to notice her? It's a classic oblivious-to-his-own-feelings dynamic. The narrative is basically about Iori dealing with her unrequited (or so she thinks) feelings while Itsuki is just... existentially devoted in a way he can't articulate yet. He's always there, but in his own weird, intense bubble.
What I find interesting is how the manga plays with the idea of 'attention.' Itsuki does pay attention to her, obsessively so, but it's filtered through his own social awkwardness and intensity, which makes it feel alienating to Iori. It's less a story about winning someone over and more about two people realizing they're already, painfully, on the same page but speaking different emotional languages. The payoff is in watching that gap slowly close.