fyi: “whom" is the correct word to use in two of the three instances.
here’s a tip: if the answer to the question is him, her, or them (as opposed to he, she, or they), then whom is to be used in the question.
there’s nothing pretentious about correctness. it’s about the nominative case vs the accusative case.
the question is not “who is next?”, but it’s “who(m) are we going after next?”
the “who(m)” is not the subject of the sentence here. it’s the object. the subject is the “we”. so “whom” applies here.
if the question were indeed “who is next?” (as you have misread it), then your point would be valid. but your entire argument stems from an incorrect premise.