I'm not sure if this is intended but I can't make plastics/sulfur like at a regular Chem Plant

Maybe you have some mods, because everything is available to me. Write down which mods you use, I'll try to simulate your problem.

Had this same issue. Had to add this in data-final-fixes.lua to resync after space age additions.

local chem = data.raw["assembling-machine"]["chemical-plant"]
if chem then
local existing = {}
for _, cat in pairs(plant.crafting_categories) do
existing[cat] = true
end

for _, cat in pairs(chem.crafting_categories) do
if not existing[cat] then
table.insert(plant.crafting_categories, cat)
end
end
end

Check in the new version, it should be fixed.

Looks to be working!

Great, thanks for the feedback.