I was going to say something similar. Start again with a clean slate, write down what car/track mods you enjoyed the most and forget the rest.
My AC is so bloated it's ridiculous, and even being brutal with deletions isn't easy because of the CM memory loss issue making the UI soon slow to a crawl.
See this as an opportunity for a fresh start and you might find AC ends up performing better than ever.
OFFER/OPTION
This is not for everyone. Requires a bit of diligence and care.
I don't have ANY of the actual data files/folders in content/cars or content/tracks.
My AC install is on an nVME drive, my AC library is on another HDD.
My car and track libraries are organised by folders which suit me and are not important in this context.
I'll written two batch files, which are placed on my desktop for easy access.
The batch files are folder drop targets. You drag and drop car or track folders from almost any file manager (even 7Z) onto them, and they take the dropped folder (or folders) and create junctions for those folders in content/cars or content/tracks, depending on which batch file you drop on. NB. NO nested folders, just single-level folders like you have in content/cars or content/tracks. There IS NO error checking. I wrote them for me. That said, you're creating a junction, not anything potentially catastrophic, and Windows does some housekeeping (can't create duplicates etc). So I don't think anything will explode, but your data, your drives, make backups.
Tech Note: A junction is like a shortcut, except for the OS. To Windows or any app that uses Widows file management, that folder looks like it's there, except it's not, it's on another drive or what-what.
So in content/cars and content/tracks, you only have junctions. Delete button in CM deletes the junction only, not the files.
This wouldn't solve the memory problems if if you just dragged and dropped ERRYTHANG, but it opens the possibility to only have what you're interested in at the moment, in your content folder.
Like say one JDM car and 6 Touge tracks. (that's how I use it, anyway). With these small numbers CM struggles less.
I also have a sandbox folder for cars and tracks I'm not sure about and don't want to add to the library before I've had a go with them.
You
could do this by copying only the cars/tracks you want rn to the AC content folder, but SSD's have a finite life and write/delete cycles like I can do now would be bad for the drive. Every folder has 100's of files.
There are some more caveats to note, but this post is long enough already.
Happy to post the batch files if anyone is interested, but I won't be tech-support for anyone's Windows install
Hah! No.