I am aware that when framing ? as a monadic/applicative construct, the mechanism implementing then is bind.
What I don't understand is how you agree that, semantically,? operates like a conjunction ("then maybe"), but still prefer a verb. The verbs, in your illustration above, are bar(), baz(), etc.
This is doubly hard to reconcile with your argument that try/? is a "happy path" construct. Conjunctions pair well with the happy path, verbs do not.
Compare:
foo.bar, then maybe baz, then maybe biz, then maybe buz
or
foo.bar, therefore baz, therefore biz, therefore buz
with your preferred nomenclature:
foo.bar rethrow, baz rethrow, biz rethrow, buz.
foo.bar propagate, baz propagate, biz propagate, buz.
foo.bar bubble, baz bubble, biz bubble, buz.
I agree that no single word will capture the full extent of the operation, but the above demonstration shows that a conjunction offers more clarity than a verb. The conjunction captures the conditionality of the construct, a quality unmatched by rethrow, propagate, or bubble.