This is the advantage of streaming. It allows the world and story to be expanded. HBO has a good track record with shows and I fully expect they will take the source material of the game and expand it.
We all know what works in games does not always translate to screen. Self exploration and interactive combat cannot exist in a show so for me I want to see the world building and story expanded by use of flashbacks, back stories etc.
A streaming show also has the advantage that it can take its time to tell a story rather than compress it into a 2 hour movie.
Four episodes in and HBO is definitely keeping to the core story which is the relationship between Joel and Ellie.
But it did as the entire episode led up to Joels slow realization that Ellie is not just cargo but his purpose. Plus it was a refreshing change to see how decent loving human relationships will find a way to exist no matter the state of the world. Episode 4 contrasted Episode 3 by showing survivors just scrabbling around to stay alive.
How is Ellie over the top wokey? Bella Ramsey captures the spirit of Ellie perfectly.