FOUND THE ISSUE!! Looking in the MO2 debug log for that line, I found it, but weirdly the line cut off like so: '...argreatwelkyndstonestatic01.ni', missing the last F in the filename and putting no other information. Which made me wonder if my very long mod name was the issue... and it was I had been putting all the FOMOD options I pick in mod names so when I reinstall I can know what to choose, and I guess MO2 has a limit on file path length.
Thank you so much for walking me through the troubleshooting!!