Update: I ended doing a complete reinstall following the guide. For a few of the larger mods that haven't been updated since my previous install I used previously downloaded files. For everything else, there were enough updates, etc. that it was worth simply redoing.
I had checked/updated SSE Engine Fixes, SKSE and other similar files in the Skyrim folder. I suspect it may have been necessary to reclean the masters or something.
Thankfully my new processor (Ryzen 7 5800) was able to do all of the LODGEN steps at the end in about half an hour total!
It might be cool to think about ways in which the STEP guide could be made more "portable", if only by flagging steps that require edits to the Skyrim install directory.
Hopefully Bethesda will simply stop making new Creation Club content/updates for Skyrim soon so that the whole thing will just be more stable for modding.
