As usual, my title says it all. I need multiple research prerequisites on the one weapon, that AREN'T on the same tree path, but I need them to not overwrite each other (setting multiple researchPrerequisite in the recipe handler overwrites the former with the latter). I've tried throwing an "s" on the end of that node, to no avail, as well as just "prerequisites", also to no avail.
The game seems to register the two distinct research requirements from BaseMakeableGun and my thingdef, but can only accept one from my thingdef for some reason.
Is there some sort of convoluted node I need here, or is it just not doable?
Yes and No.
So, when it comes to adding research prerequisites to the recipe Maker itself, no. It can only have one. (For reference, building thingDefs can have multiple using a different tag).
You can get creative:
A prerequisite for the work bench and a separate prerequisite for the item itself
You can make the item require several parts, of which each part has its own prerequisite.
Yeah, I tried using the buildingDef tags at one point, just in case.
Ultimately for now I've just assigned the "highest" research as the required one, although your ideas of gating the workbench/using multiple parts with their own gates are both solid suggestions :D