How are these Pan-American destroyers meant to be played?

That seems to be the intended lane. Their AP can bite hard into broadside targets, but the high arming threshold makes lightly armored destroyers an awkward matchup. With average concealment and limited speed, charging into a capture area to pick a close fight sounds risky.

Look for chances to shoot at larger ships from a safer angle. The torpedoes are short-ranged, so they seem more like an occasional close-range threat than the main plan.

The interesting part is how the damage tools fit together. From Tier VI, the branch gets a Main Battery Reload Booster, and from Tier VIII it gets Combat Instructions that charge through gun hits. You can use the faster reload to build charge, then time both effects together for a stronger burst.

That doesn't erase the low base damage output, though. If the target angle or armor is wrong, firing faster won't solve the basic problem. Pick targets carefully and save the combined boost for a useful window.

I'm not sold on the destroyer-fighting side. AP-only guns that can struggle to arm against lightly armored ships, plus weak short-range torpedoes, could leave you with few good answers when another destroyer gets close.

The Repair Party should help them stay in the game, but it doesn't sound like a license to trade freely. Their strengths look more dependable when shooting at exposed, broader targets from the flank.