This isn't one of mine, but lettuce nudibranchs are great algae eaters! Some sea slugs, like the leaf sheep (2), sea bunny slug (3), and fairy/cyerce sea slug (5), eat very specific algae and nothing else. I've looked into it. They're so adorable.
Grew up in suburban midwest USA. As middle of the country as you can get.
It wasn't until I moved to the Pacific Northwest of the US that, like you, I wasn't an aberration, I had just grown up around trash people.
Started downhill isn't right. Accelerated is closer.