With the default seed (20260401):
The rare metal processing science pack takes empty DT-fuel cells
Empty DT-fuel cells are unlocked by fusion energy
Fusion energy needs depends on rate metal processing
Rare metal processing is required to progress

Fixed in 1.0.4 (basically, there is a hidden recipe that provides the DT-fuel cell functionality which is enabled from the start, and the code was assuming this means you can craft empty cells) - unfortunately, this does mean the recipes will be rerolled :(

Please tell me if there are any other softlocks!