Well the series being stupid so to speak is part of the point I think. It's a very self aware harem that's very intentionally playing around with a lot of tropes and leaning into a lot of absurdist comedy, it feels like it's made by someone that got tired of most harems not actually being an actual harem so they went I'll do it myself with 100 girlfriends.
A lot of the heart comes from the fact that Rentaro (the male MC) is an actually extremely diligent boyfriend, and it's one of the primary reasons why the series is maybe the only het harem I don't hate. He'll do things like borrow the book one girlfriend uses to communicate via pointing out words and sentences in the book, and he scans the whole book into a text to speech program he puts on her phone, making it much easier for her to communicate since the phone is smaller and easier to use, plus the words are now spoken aloud so she can basically talk. It's that level of care for each girlfriend, which to my knowledge is unheard of with harems.
On top of really embracing the comedy part of being a rom-com, such as having the harem enter an eating competition where they all have to work together in order to defeat someone that's using some ridiculous costume and machine to cheat. Also the whole reason they enter the eating competition to begin with is because all of the girls want to get to know and bond with the new girl that loves eating. Which is a factor throughout as well, where the harem really bonds and cares for each member of the harem.
The series is not for everyone of course, and I understand if people don't like it, I just think the author made a rom-com harem where they really put in effort into both romance and comedy.