A structure is not the same as a rigid template
A fixed template filled in the same way every time is what produces robotic-sounding captions. A looser structure speeds up writing without forcing every caption into the same shape: a hook, a point, a call to action, in that general order.
Write like you are talking to one specific person
Captions written for "the audience" in the abstract tend to come out generic and a little stiff. Writing as though explaining something to one specific, real person tends to produce both a faster first draft and a more genuine-sounding result, since it removes the instinct to hedge and generalize.
Keep a running list of phrases and openers worth reusing
A short, personal list of hooks, transitions, or phrasings that have worked before saves time without producing the sameness of a formal template. Pulling from your own proven language is a different thing from filling in a generic blank.