Gerald much research has gone into all the questions you ask, the metaverse as meant by FB has been a holy grail for a long time, the conclusions of those prepared to admit it are that it can't be done at profit, because a fundamental requirement is an underlying live digital twin of the real world, everything between that and the real world is the space of mixed reality that we would all be living in, whether we like it or not.
The reason it can't happen is exactly the same as why a succesful vaccine killing all covid can't happen; profit.
A succesful vaccine would have been something developed jointly by all countries for all people.
But it became profit driven, so we see many competing efforts, with the result none will be given to everyone.
Profit, is the thing that has to be gotten over in order to get to a successful vaccine, and a successful digital twin, and any other world project that must be collaborated on.
There is actually some hope now we are realising profit is also the underlying driver of the environmental problem.
So who knows, it might happen very soon.