Fleet

Hound’s Tooth makes most of them a walk in the park. Otherwise, I’m not sure, sorry. I think I did them with a solid Home One Rebels fleet.

^This^

Pair Hound’s Tooth with your silencer and Vader, and that’s how I 3 starred it. If that’s the Enfys Node, just know that that is a really long farm.

We also have more direct counters, now.

So what fleet is your enemy at 5A (Hard)? If rebels, then empire with TIE Bomber probably minimizes gear investment.

So on & so forth. It's often just as much about who you use as it is about how far they're upgraded.

I'd recommend investing in Hound's tooth. It's still the best ship out there, and will make a lot of things easier, ship-wise. You could probably 3* it with your current fleet and a hounds tooth. Run Silencer, HT, ITF. For reinforcements I'd go with TIE Advanced, Scimitar, and then either Ahsoka or Slave 1. Also, unlike squad battles, you can get 3* with one defeated ship.
One more thing that may help is unlocking Chimaera. It's a generally better ship than Executrix, especially for campaign, since it can heal/control TM.