eh i don’t think most of that is true, pretty sure the dreams you remember are only the insane ones because you actually make an effort to remember them when you wake up.

To my knowledge dreams exist because our brains use the downtime of sleep to run simulations so we can practice stuff and sort of prepare for unexpected situations.

i think the reason we forget dreams is just because there’s no point in keeping it around, the brain has already benefited from the dreams and it’d be unfortunate if we mistook a dream for reality and screwed something up because of that.