
The third wheel best friend actually distrupted the natural flow of MC's relationship development so the story has lost its impact at reflecting character development and their emerging feelings over time. They probably had wanted to add a playful and fun character to make story more enjoyable but the story and plot didn't need this character and his function ╮( ̄▽ ̄)╭

Kengo's love seems more sincere than maya's love to me because it's actually hard to dedicate yourself to an unpredictable relationship after a certain age and experience. Kengo had to risk his stable emotinal state and life order and, out of his comfort zone so it isn't a thing that you could do easily for a random person so you only do this for someone special.
Maybe seme hadn't realised his sexual orientation that day but he absolutely had found out about his cos-play fetish(≧∀≦)