How much should your partner spend on an engagement ring?

I've recently fallen down a rabbit hole of practically every single person I know getting married (I thought the "ring by spring" saying was just a myth but it's startlingly true????) and I've now seen a LOT of rings.

Of course, when you google anything about engagement rings you are bombarded with posts calling women who want larger diamonds "gold diggers," "materialistic," blah blah blah. I thought that a ring was supposed to be a serious investment that shows monetary commitment to the relationship?

IMO I have seen lots of rings that do not exhibit life-time durability. I like moonstones and opals, but they simply aren't a hard enough gemstone to hold up against everyday wear-and-tear. I think Diamonds, Moissanites, Rubies, Sapphires, and Emeralds are the only stones hard enough to last (and even rubies, sapphires, and emeralds can show a lot of scratching after years of wear).

I have chatted with friends who claim not to care about what their engagement ring looks like, and seen countless women online who brag about how humble they are and how they asked their spouse to buy them some cheap $50 ring so they could put their money towards "better" investments.

BUT the number one thing I have noticed is how women are 100% judged by the quality of their ring. Socially, rings seem to signal "Hey! I have someone who cares about me" OR "...oh, that guy doesn't like you that much, huh?". I think rings play a larger role than just a shiny rock that's a representation of commitment between 2 people. Knowing this, it seems cruel to buy your partner a cheap ring and know they will face ridicule for it.

That's a bit besides the point. Mostly, I want to know, what do you guys think a ring should cost?