I'm not sure if this is a bug, or a limitation of my PC

What is the exact settings you use in Difficulty.eco?

I'm not able to reproduce the issue with this file, but the settings are indeed extremely at the border of what is possible at most of the settings, especially in regard to the CraftTime, CraftResource and ConnectionRangeMultiplier (the latter having an explicit warning of having severe performance impact at doubling already, you 10x it) - I'd hence recommend to check if that issue also happens with more normal settings.

Glad to hear it's working now. We may set some lower and upper limits for the configs in the future, but so far I've actually never seen someone using such extreme settings, so it may not be necessary to begin with.