Okay, so what DOES Chara do?

I'll admit that I haven't really interacted with the Fandom since the "Chara is super evil and forcing Frisk to do Genocides" idea was popular, but I've recently started interacting again since I started Deltarune and have noticed a wide shift in Fandom perception of the characters. The problem though is that I've seen a multitude of conflicting opinions and the Fandom pages are not helping.

To get an idea of where I'm at, my working theory up to this point was that the first Genocide IS Frisk's doing, but any and all runs after that are canonically Chara since Frisk like, sold their soul or something and that's why it always ends with their eyes flashing red all evil like.

I genuinely have no idea what to think anymore and would love some insight from people more well versed in the lore.