The UN are a faction I will port to SPT 3.11/4 soon.
In SPT 3.9.8, I used the tiered bot loadouts system in Realism Mod to split USEC into 4 factions, the UN being the lowest tier.
That was before I designed their weapons from scratch. When I incorporate Realism into 3.11/4, factions won't be levelled. They'll have unique strengths and weaknesses.
Lorewise, USEC no longer represents Terragrroup. They're a UN mission force of American/European soldiers and mercenaries.
UN guys from 3.9.8.
SPT 3.8.3 Realism tiers from left to right; Tier 4 USMC, Tier 3 USAEF, Tier 1 UN.