I am gonna tout Mike Shea's "Return of the Lazy DM" @SlyFlourish , got a website an all, tons of advice on low prep rpgs
The "bring one piece of content" failed utterly.Nobody was willing to do any homework outside of game night.
If I were to do it again, I'd lean into the "players create the content at the table" aspect. Microscope worked really really well. I'm not sure how it would work, though—creating NPCs, encounters, maps at the table? I think it's more common in rules-lite games, but my players prefer 5e. But it does seem like there's some potential there for a truly low-prep approach.