Bioflux processing does not unlock the bioflux plastic recipee. That's unlocked with the "plastics" technology - which is not unlocked unless you discover another planet
https://i.imgur.com/9rk263Y.png
Sulfur processing is the same, it's unlocked with the "sulfur processing" technology which is unresearchable
I have all t2 techs - no mods that mess with tech, and can't make plastic or sulfur
Edit: I cheated in the discovery of Nauvis to get around this, but I still wanted to write of this issue
If anyone else is reading and the issue persists the command is:
/c game.player.force.technologies['planet-discovery-nauvis'].researched=true