But there are two differences in understanding: a "find another description of the timeline" and b "this crossing is irreversible"
In fact, as four-dimensional creatures, we have the limitations of this space in essence, which has nothing to do with our level of understanding of the universe.
Our usual time axis is similar to the historical year. Of course, I know that the coordinate axis you mentioned is at the same level as the three-dimensional coordinate we know now. So my question is, what ability do we have to control this axis, just like we can move freely in three dimensions: in fact, we are still far from this ability (at least for now).
Now it is more reliable to realize time travel according to the principle of relativity. For example, flying in a high-speed aircraft is actually our movement in three dimensions. When it comes to real-time travel, we have to talk about the "wormhole" theory, although it is very rough.
According to the wormhole theory, we don't go back in time travel. The most typical classification of wormholes are Euclid wormholes and Lorenz wormholes. The former exists forever, while the latter exists randomly. Theoretically, if we find the entrance to Euclid's wormhole, we can travel through time and space at will, but remember, the current theory does not allow any time and space travel to change history.
In wormhole theory, there are still no reliable theoretical support for maintaining wormhole entrance and wormhole exit, and even the current theory does not allow it. Just imagining.
Finally, our three-dimensional space is real; Relativistic time travel, black hole theory is a reasonable assumption; But the wormhole and white hole theory is just a frivolous guess now. Although science never excludes imagination, we should not go too far. I am also an astronomy enthusiast. The above is my personal opinion. Welcome to communicate. We seek common ground while reserving differences.