There are "low hanging fruits" - easier to achieve goals -, and there are super-fruits, milestone-fruits.

Among the most important ones:

-- the long-known Problem of Transparency, applied to the apparent emergent intelligence in NNs. Why does it happen - in detail?

-- then, a Theory of Apparent Intelligence through NNs. Transforming the results achieved into a Science. Which allows to do what we are doing - but in a lean and targeted way.

-- then, a General Theory of Intelligence, that includes the above to go beyond current architectures and get those features of Intelligence we expect and still not have.

The long-term direction we got into must lead to this.

(You note a ponderant detail of the above when you note the importance of explaining the emergence of a World Model from a Language Model.)