Responses
Not sure if the volleyball one is "Dig It!"
I tried searching for the otaku one too and this one seem to be it
https://www.mangago.zone/read-manga/seiryaku_kekkon_wa_otakoi_no_hajimari/
1. Sports manga, not haikyuu but its volleyball. All I remember is it's new, plus, guy is like pressured to be like his dad(?) A great striker. But then he wasn't good enough so his dad taught another guy. Which then lead him into not be the best stricker but rather a libero??? Cuz like, his dad have crazy spikes and he wants to return it(?))
2. Slice of life(?), guy and girl gets force to marry but turns out both of them are otaku. They both find out about it when they bumped into each other in a concert lol. Guy have dark hair and girl have light hair (i think)