Isekai, the usual transmigration, reincarnation, time travel etc. except, you know, it's gay
Mc is pretty much just an airhead when it comes to love, he's the type that will continue to pursue one goal and not think of anything else while achieving that goal. For something to be a harem, the guy must reciprocate the feelings of all the girls that show interest in him as well. We can clearly see that he doesn't hold any of the ladies into a romantic aspect (at least for now)
Guys, version 2 of this list is up!
LINK: https://www.mangago.me/home/mangalist/2658246/
I stopped updating because transferring manhwa from this list to the other vice versa is a painnnnnn