Thanks for writing this. Some time ago, I also wrote on the possibility of microorganism suffering. Feel free to reach out if you’d like to discuss the topic :) From the intro:
At any given moment, around 1030 (one thousand billion billion billion) microorganisms exist on Earth.[2] Many have very short lives, resulting in massive numbers of deaths. Rough calculations suggest 1027 to 1029 deaths per hour on Earth.[3] Microorganisms display aversive reactions, escape responses, and/or physiological changes against various fitness-threatening phenomena: harmful chemicals, extreme temperatures, starvation, sun damage, mechanical damage, and predators and viruses.
Higher-variance outcomes seem more likely with a U.S.-led future than with a China-led future.
This might be one reason to think that worst-case outcomes are more likely in a U.S.-led future.