with a single account (isn’t that the point of the fediverse?).

Absolutely not. I’m not sure why people see Lemmy, Mastodon, Pixelfed, Peertube, Loops, etc as all the same thing that should all be one app.

They might communicate with the same protocol, but they have vastly different uses, interfaces, purposes. It like saying you want one vehicle that drives like a motorcycle, haules the kids around, gets great mileage, and can tow 20,000lbs.

All your tools fit in the same toolbox, but you use each one separately for the use it’s best suited. Then you put it down and pick up another. Sure you can make a multi-tool but it won’t do any job as well as a proper dedicated tool.