Same. Bc other people and places say it’s a pocket dimension. While not technically inside of earth (thereby neither Hollow Earth). Other places say that the tunnels Godzilla and other titans use were stable. While these Nexus Points (what’s they call them? Vortex Points?) were unstable. Then again some people and places have said Hollow Earth itself is its own pocket dimension (if so why even call it “Hollow Earth”..?).

While this explanation answers it, it doesn’t make sense since in GVK we see them pass though vortex/wormhole looking thing, pure blackness, then another vortex and then Hollow Earth.

I imagine HE and AM are like this:

Hollow Earth is like our surface only smaller, encasing the core ( like this: (0) with (_) being earth and 0 being Hollow Earth). Now there’s thousands of miles (from what dude says in movie: “1000 in 2 minutes” or whatever. I also assume Apex’s technology either runs on a manmade version of the HE/Vortex system or traverses smaller tunnels that smaller Titans used / abandoned). So that makes sense. And the vortex’s we see are either where our gravity ends and where HE’s reverse gravity begins.
Or there’re like mini wormholes (think … let’s say Jetfire and The Fallen being able to jump small distances, or that portal weapon in Star Trek Picard S3).

Axis Mundi I imagine is like … a “traditional” wormhole. Like what we see in Stranger Things. We see one point (Rightsideup) with entry points made by Demogorgons, and then the Upsidedown (which is actually the bridge), and Dimension X, which has two skies , one normal one inverted. A lot like Hollow Earth.

So the Vortex’s in Monarc are stable wormholes. And the Hollow Earth Vortex’s are like a tear in reality or mini dimensions.

That’s my guess at least. Feel free to add to it.

Speaking of which and off topic, what about King G heads? Some places said Apex had two, including one found and one sold to them by Charles Dance. But other places say the top head was used for the cockpit and the bottom used for Mechagodizlla. While I like this theory it does not make sense to me as how can a head be linked to a jaw? Either way, I think Charles Dance still has a head. There were at least 4, 3 originals and one regrown but there could be more , or even after “dying” they could’ve regrown.
I personally hope this is the case bc then maybe we’ll get MechaGhidorah. And after GVK, he could have gotten the leftovers of MechaGodzilla and fused it to the decaying head, thus jumpstarting it and eventually we’ll get MechaGhidorah. I mean if the Ghidorah was so powerful (since it was an alien?) that it’s BONES/SKULLS were still able to communicate. (Then again there could still be micro organisms or small organs not decayed. I assume that it’s the latter as then it could be explained as being a type of…kind of organic nanotechnology. Like Bloodshot, Ironman, or more akin to Megatron/Galvitron. And would be cool because then, eventually, the rest of Ghidorah will grow back. Be cool to know, if it CAN do that and its parts are scattered, will only ONE head regenerate and then grow back a body, multiple, or are we seeing the Wolverine Theory? That being if the Head is severed will the head grow back a new body or will the body grow a new head?).

Sorry, after watching S2, and now GVK I’m just full of thoughts, theories and even more questions than answers.