But I no longer understand where this manga is going or what's going on except for the fact that it's horny
Well you see, there is plot (with the Reincarnated Witch)... but the author asks: "Why plot when can haremslop?"
The best thing about Haremslop is it's self-defeating too. Either it actually rolls with the harem route and all the girls get to win but it fails to commit to actual polyamory or anything, so the story just wanders vaguely and ends hazily... or it doesn't roll the harem route, in which case woe upon you if you aren't on team main girl, because main girl is almost always predestined to win if the ending isn't full harem.
Fortunately, I am on team main girl (the Witch) this time, so I'm probably safe if it's a single-winner ending. Let's see if it is, or if they go in the harem direction if they just keep piling on the haremslop or actually do anything interesting with it...