In my opinion, none of the above, at least not as a first resort.
Door #1 is the Meguiar's 3-step marine fiberglass restoration system- deoxidizing, polishing, and waxing. It give a decent satin sheen on weathered fiberglass, not a like-new high gloss. It improves with repeated application. After the first round you only need to wax if it still beads, or polish and wax if it doesn't. I wax twice a year for uncovered storage in our high altitude AZ location. I believe 3M makes a similar suite of products.
Door #2 to clean and deoxidize using a mild, fiberglass-friendly product like Barkeepers Friend, then apply a high gloss liquid flood wax (Zep). It'll take 4-6 thin coats wiped on to achieve a gloss like new gelcoat. It lasts 1-2 years depending on exposure, then you strip and reapply.
For mild to moderately weathered fiberglass, I'd probably try the first approach. With moderate to severe weathering, go straight to the second.
is usually only needed after major fiberglass repair.