Since the game goes through so many changes and shifts so much. My guess would be mid 2025. Using the devs team's resources and time to focus on refining and balancing the newer features and re-envisioned events, adding more GE levels, etc. To later down the road focus on figuring out what they wanna do with the space hub or what they want it to be.
Personally I'm rather hoping on something modular. Something that serves as an platform for an end-game feature. Up on which can be expanded upon. To motivate players to get there and when they get there to keep on playing. Not even GB's lvl100+ projects will be able to keep us playing. Eventually we'll get them to a given lvl, play with it for a while and than quit.
That been said, it's all hopeful thinking/speculation. Seeing how it's going... it's rather hard to place the finger on the right spot