So turns out that if you install a mod called Carbon Steel which modifies the steel recipe to require either coal or carbon, while you can still progress on Rubia with it, you're limited to just extracting what steel you can from the piles lying around. This makes the beginning portion of Rubia where you need to yeet 1000 science packs excruciatingly slow.

I don't know if anything can be done for it, but it isn't really an issue once you past the 1000 science pack issue early on, since Metabolic engine disassembly solves the steel problem to an extent.

Thank you for the report. I won’t be able to make compat for this for a while. My recommendation for the time being is disabling Carbon Steel until you have completed Rubia’s Makeshift Science pack stage, then reenable it.