This is "Chanto Suki tte Ieru ko Musou" but if it was weekly instead of monthly upload
Its similar, but also not? IIRC in Chanto dude is a bit awkward but mostly normal dude, he kinda rizzed up 3 girls who now are pinning after him, but all were wishy-washy/shy/secret about liking him. Then a new girl came to school, he managed to rizz her up with his idiotic bullshit, and as she is open/honest she outright told him she likes/loves him and started pursuing him openly, while the other 3 still are hiding behind the scenes if you will.
This one at least based on first chapter alone seems to be a slightly different thing. Dude thinks a shit load of things in his head, overthinking a lot, got rizzed up by a sister friend who for 99% sure saw him like a "bonus" little brother and was a bit to affectionate towards him, which he interpreted as her loving him. His assumptions fucked him up when she married enough that he flunked and didn't get accepted to school he wanted, but it also made him overthink shit even more. He thinks to much, yet still manages to blurt out stuff that seems to made 3 girls interested in him. Childhood friend who for sure will lose, and seems to be yandere? Classmate, and probably far separated Cousin for it to not be full blown incest. We didn't saw the new girl being rizzed up by him (maybe its in chapter 2?), plus she is presented in ch1 as some kinda mastermind?
So like Chanto seems a cute romance with 3 "tsunderes" of sorts if you will fighting with 1 open book "new" girl, while this seems to be 3 girls vs a manipulative mastermind. In chanto dude seems normal, while in this dude is a mental wreck and his overthinking shit will probably lead to to much drama.
Won't stop me from reading it anyway XD.