Which ones have more synergy?
Also, is the pay off of 5* Alchemers good?
Which ones have more synergy?
Also, is the pay off of 5* Alchemers good?
None of these weapons synergize in any particular way with each other. Alchemers and Brandishes do lots of damage and similar statuses. Antiguas do medium damage and in one case poison.
Antiguas are easy to use, and they are handy for breaking blocks and minerals. They have no other virtues. Alchemers do more damage in the hands of an expert who knows how to exploit the ricochets. Alchemers are more fun, because they reward skill instead of just constant clicking. Alchemers offer more useful statuses.
So my answer to your question is: Use Brandishes and alchemers, because they are some of the most powerful weapons in the game. Don't use Antiguas, because they are comparatively weak.
Depends on your playstyle...
If you spam combos then Antiguas and brandishes go better together since you already work out that attack button.
If you like to use charges more and can play without AT then Alchemers are good to have. (they also work good if you plan on stacking statuses like poison, fire, and shock)
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The Pay off for alchemers is good (can even be better than Antigua in crowds) if you learn not to empty the clip and how to snipe with that charge attack.
Antiguas are good if you want to get an enemy's attention, deal damage, or just not run out of clip ammo so fast.