Navigable if you can survive the intense radiation at the galactic core.
The radiation levels near the galactic core due to the density of star population would make surviving the journey impossible.
Where does it say the wormhole is at the core? It implies the entire galaxy “is a wormhole”. So where is the evidence that a single object in the galaxy disappeared or appeared through this wormhole? This whole idea sounds like an attempt to come up with something new, for the sake of making a name for themselves.