Question: are benthic gear stats random?
Answer: The intro quest to the Benthic system will provide you with one piece of ilvl 385 Benthic gear which you're going to upgrade to ilvl 400. Benthic Gear has predetermined stats and there's no RNG involved. Benthic Gear (ilvl 385) can also come from Nazjatar World Quests (Source).