I feel like authors currently would always hae to go with multiple endings(Similar to visual novels), because, think about it(Especially romance/harems),
it would be disheartening, if not devastating for viewers if it was a simple 1-person ending, and the author chose the character you didn't pick.
So there's basically only 3 result I can think of, especially since this is a mystery-thriller harem with the likes of hinting at stuff beinmg hidden in the background(Especailly that part in the chapter revealing the news about "Love-eater hunters" being real and ruthless).
1. Endings where each chapter is dedicating to each character winning, similar to some oher harem mangas or mangas like Btooom! containing both different results depending on what actions the characters tak
2. A harem ending, it's as straight forward as it sounds, the MC gets everyone, no harsh feelings, and it's those "Happily Ever After" endings, although it may sound like a cheap way to cut it, I always feel like this is the safest choice as a secondary ending, like after the endings in (1.), as it satisfies everyone, and it's defintly possible consideinrg this manga also wants to dive into the territory of "forbidden relationships"
3. Tragedy ending. Similar to the person who commented b4 me, I feel like this is also a highly likely outcome that would replace (1.) as the primary ending. It's simple, and proves how gritty real life can be at times, it woulodbe tragic to see this as the only ending though, and I would like this to be one of the endings, and not the only ending.