everything that (i think) happened while i was afk:
automated rocket launches, endless research, many buildings requesting speed modules that had not yet been crafted had all of them crafted and delivered, a nuclear reactor i had just set up began running at some point because i had the fuel rods only being crafted once all my kovarex enrichment centers were self-sustainable.
things i tested already:
i made a new save and it ran fine, i created copies of my broken save they all ran as bad, i canceled my research and turned off the nuclear reactor to no effect, i set all the graphics settings to their minimums to no effect.
debug screenshot:

log file: save: