Hi, I did Eliot last year in the HSC I'd also say that Journey of the Magi is a pretty vital poem to talk about since it really shows Eliot's personal intellectual & emotional journey!! Obviously though it's important to consider the question so don't just throw in any poem for the heck of it - think about what's going to support your line of argument the best.
typically you would do magi + hollow men + one of the first three (so prufrock rhapsody and the other one which no one cares about). that would set you up for better discussion as the first three are the most similar thematically, but hollow men and magi are much more distinct as they showcase eliots growth the most, which is why most teachers suggest using them.
My teachers approach was external world and observations (preludes, rhapsody), internal/psychological (prufrock, hollow men), and spiritual (magi). I’ll probably be following fairly close to this for trials and hsc