Sorry, not meaning to step on anyones toes here. But this is a bit frustrating.
The export user-settings in InDesign is crappy, reported that in the latest realease allready but it is not working as expected.
The supposed back-ups of illustrator-settings seem nowhere to be found.
I have Time-machine running and even a backup of my macbook on an ssd. But I cannot find any files that should be the workspace or shortcut pref. file (with the corresponding name) for illustrator.
Not in library-application support; and also not in the (expected location) Illustrator-presets folder.
If you have Time Machine, then go into a backup that has been made before the update. And then the files are here: https://www.vektorgarten.de/illustrator-settings.html
Which backups cannot be found? The ones you create with the Settings export? They should be exactly where you saved them. It's a packed file. You can add .zip as the file extension and then unpack it. Or you can re-import the package into Illutrator.