Being able to use your skills in your sleep has some pretty horrifying implications. Imagine if someone muttered Fireball in their sleep and burned down their house.
Probably because the usual you save me want be slaev trope in isekais but the only actual explanation i can think of is because they cant party due to his thingy at the start that doesnt let him form parties
Well... This adaptation is made for a shounen rating at most, seemingly.
I don't know when he actually sexes each character, but if that has already occured by this point in the LN/WN, then there's no way they'll suddenly bump up the rating of the manga now.