I don't get Umineko

I read through I think three "episodes" of Umineko, and I don't get it.

Ostensibly a mystery kinetic novel, it follows the fate of Battler Ushiromiya, a strapping young lad, as him and his rich family convene on a secluded island for some family business reasons. Idk. Then there's a witch? And people die repeatedly.

Then there's the designated tsundere segment, which was fun I guess.

"Fun I guess" sums up the entire thing for me. I can't say I was outright bored, but things just... happened. I very quickly stopped caring about the mystery, because the answer was always "who cares, Beatrice is fucking with Battler". Then some blue space witch tea party thing started happening and I was pretty much just lost? And that's before the PoV shift to a heretofore completely unrelated character, like, hours upon hours into it.

I don't understand what the core appeal of it is. I don't understand what the plot is, or why it has to be how it is. The only thing I know is that people seem to like Beatrice.