there isn’t enough content on Lemmy to only whitelist certain communities

This is really the central problem. There's way fewer posts on any given Lemmy/fediverse network compared to the major players, and I've been conditioned by the last 13 years I spent on reddit to have constant interactive stimuli and discussion based on my interests. That doesn't exist here because the communities are so small. Admittedly, yeah, I could post. But I've always been a commenter on existing discussions, not someone who wants to start the discussions myself.

The relative lack of content on Lemmy, for me, has been a boon. I go through New, then Top 6 Hours, then Top 12 Hours, then I need to find something else to do. When I was on Reddit, I found myself bouncing between Reddit and YouTube for entertainment. With Lemmy not having boundless amounts of crap to scroll through and no algorithm, my tech usage is far more varied.

There is for me. And (almost) nothing I subscribe to are those non-low-effort communities.

I also don't doom scroll for hours at a time, so maybe that's partly why.