Good news: it’s meant to be a variant upgrade to the mitochondria, requiring much less dedicated graphics. It’s described here under the “Upgrades” section for Mitochondria, though I spelled it as “Hydrogenosome”: Upgrades, Unlocks, & Endosymbiosis Master Thread
Hydrogenase is a more ubiquitous and “standard” enzyme present in most microbial life, while hydrogenosome is a membrane-enclosed structure.
Essentially, it’s an anaerobic upgrade to the mitochondria, detaching the mitochondria from an oxygen requirement at the cost of efficiency. What Buckly mentions on the Discord I think would be good, where it either has a base productivity that doesn’t scale with O2 and works in anaerobic conditions, or it becomes more performant the less O2 there is in an environment. I think the latter would be best for balancing reasons.