Nah this is more of a me thing than a writing problem. I just play disconnected from MC's in general but I get into all the other characters alot. I'm like this with literally every AVN and AAA / AA video games as well even ones that have really good stories. I just don't get into main characters I never once really found my self caring about a Main character always cared more for the characters around them. Probably from years of playing normal games in general where all I cared about was having fun , the gameplay and what happens next in the story but never making any choices in a story for what made sense for my character but what I thought was fun or min maxing dark / light side points or what have you.The fact that you don't care the MC, when you are playing as the MC, is proof that most MC are badly written. And if they don't know how to write a decent MC (Main Character), how it's possible they can write any other character?
But writing is subjective I personally have a hard time noticing bad writing in 90% of AVN's I play because of how I play in the moment and thinking about the context of what is being said and not ever thinking critically about the writing.