"If Meta wants…" My concern is that the only conceivable motivation Meta could have for investing money in such a project is making more money. If, in the process, Meta destroys the eco-structure of the Fediverse, so much the better—less competition, more money for them.

Absolutely believe in chronotypes. Retired now, thank god. But my best REM sleep has always happened somewhere between 5 am and 9 am. Even when I had to follow everyone else's schedule, I absolutely had to be able to sleep in Saturday morning. If I didn't, at some point I'd have to go off in a corner later in the week and just sort of waking-dream to catch up on REM.