I agree on Google and Apple being irreplaceable. But Facebook is easy to leave.
Same goes for Gmail. I have used my Gmail address for countless services and it’s almost part of my official identity. The benefits of moving away from Gmail doesn’t justify the effort I have to put in
This has been a topic for over a decade now, I think. People have been recommending getting your own domain. Best time to do that was ten years ago, and the second best is today.
And it's not viable to propose any alternative. There is no platform, closed or open, where there are enough people registered to be actually usable, and nobody will make a separate account for this.