barbjatkin The game is going to have issues with that much CC. At some point you're likely to have many duplicate files, many old files, files that are merged so you can't find them if they're listed in Previously Broken mods and CC or the current pinned Broken Mods and CC thread, files that had special installation instructions you may have missed, files whose requirements have changed, and files that conflict with each other.
I recommend testing only those new files, in a refreshed Mods folder (rename the old one, delete localthumbcache), and adding them gradually, to help narrow down conflicts. Do also check the known broken content lists here. When you add your other CC back after solving this issue, do it in batches.
Use this as a chance to reorganize and pare back to make your folder more manageable. I recommend organizing by creator name, as a way to narrow down duplicates. Delete files that are merged multi-creator files (and avoid these generally). Consider deleting things you've had for a long time but have never used.