A: Beautiful women have a worse personality

This one may be easier to imagine. Beautiful women are mostly loved unconditionally and thus never have the need to develop a personality. They need no hobbies, no passions, no greater purpose, nothing. They can afford to put zero effort into who they are because they will be loved anyways. This makes them

a) extremely boring

b) become bitter and resentful against the world as they age and their beauty starts to fade, making them realize the only pillar their life is built upon is falling apart leaving them with nothing

B: Beautiful women have a better personality

This one is a bit more controversial and surely hard to swallow for many people. The idea is that exactly because you are beautiful, people subconsciously treat you better (there are many studies showing this). So you are given more love from the world, which indeed turns you into a better person. You come across more trustful, so people trust you more. They are nicer to you.

All this is triggers a postive feedback loop since people enjoy being around someone who is happy (or makes them happy). It's almost like seeing the world with pink sunglasses, with the only difference that the sunglasses are inside you and can't be taken off, making it real. In the end it's a great incentive to become an amazing person and use your "power" to better yourself and the world.

I think there is some truth to both, and it depends on the person. A good analogy could be that of someone born into great wealth: they can either become spoilt pieces of shit, or great philantropists who use their power to help others.

But which one prevails? I think that when seeking very attractive women (which most men do) it is of primal importance to make sure that person tends toward the B type, and shows no signs of A, which will turn into toxicity of the highest order.