Slitherine

I researched the Orbital Relay tech, and in the list of things it can make is a Geneseed Bunker.
First, it's missing from the research list.
Second, why would I want to build this anyway? All it does is grant 6 Influence with a power upkeep of 3, when I can build an Assimularum that also grants 6 Influence with only an upkeep of 1 power.

It's not missing, it's part of the questline. You can begin constructing them when you reach a certain stage of the quest, chapter 5 or 6 I think, and the requirement is to build three of them to continue.

It should be written in the beginning of the tooltip that the bunker and its research are exclusive to a quest.