Okay so the explanation for "Under the Silver Lake" was so obvious (I thought) that I was waiting for the reveal, and then it never came, and then I looked up explanations online, and they also didn't arrive at the same explanation. So with significant spoilers in mind, here is my theory:...

This film got dragged for how slow paced and simplistic it is, but it honestly was perfect to me. It's one of the most unique and believable horror concepts I've ever seen and I thought it was executed to a T -- with the drawn-out nature of it just adding to the atmosphere. YMMV but I thought it was fantastic.