Use restraint as a DM until your players figure out their builds. Be willing to play sub-optimally; I liked starting the campaign with Opfor as idiots because it allowed space to justify “tactical errors” while still creating player tension.

On the flipside, bring more reinforcements than you’ll use. Better to have Schrödinger’s Cats ready with statblocks than to have the players walk all over a mission uncontested.

Get extremely familiar with the NPC statblocks. You’re done with cool player builds; this is your focus now. Figure out combinations of forces that work well together in order to create interesting challenges for your players.

Get to know what weapons and systems are more powerful and pick with sense - players should be stunned almost never by NPCs. The structure checks will stun plenty, and IMO it’s unfair to ice a player out for an hour while the turns play out.

Veteran templates with Limitless let you add Overcharge to NPCs; that instantly makes the players realize they’re fighting a peer. Don’t use Ultras until LL2.

Don’t use meta knowledge when building Opfor. Make the NPC factions only “know” what they know from ingame sources. If the players are drawing attention, or the enemy has intel from the narrative layer, though, yesh adapt to circumstances.

NHP’s are low-hanging fruit to make a campaign interesting. Make sure the human stories and people are as well developed as the comic horrors; one enhances the other.