The definition of meta has changed over time. My understanding is it got the current "abstract" "thing aboout itself" definition long after the term "metaphysics" was coined, which probably originally meant "things we don't have a good name for but should probably file after the stuff about physics"

> Metaphysics = the physics of physics

Metaphysics isn't really the "physics of physics" though. It is part of philosophy, not physics. It isn't even the "philosophy of physics", since that names a branch of philosophy distinct from metaphysics (albeit they do have some points of overlap.) This is an example of where the meaning of a term is different from the sum of its parts.

The philosophical implications of quantum theory (and its interpretations) is one part of the philosophy of physics, but the study of those implications go beyond just metaphysics proper and also extends to other areas of philosophy such as the philosophy of mind, epistemology, the philosophy of logic, etc. Conversely, there are some debates in metaphysics with which contemporary philosophy of physics doesn't concern itself with much, such as the relationship between existence and essence, or the problem of universals.

I think that in the context of AR they actually are trying to talk about "universes that describe a universe".

A "metaverse" is a "universe" in the sense that it's a shared 4D spacetime that you can explore (using some technology to give you a window into it). It's "meta" because it's layered on top of our "base universe": It's there to describe and augment the physical universe we exist in.

For example: If, in your vision (via glasses, or a HUD, or a pane of glass or a brain implant), there's a big 3D arrow hovering above a road then the arrow exists in the "metaverse" and the road exists in the physical universe that the metaverse is describing.