I haven't used an app cleaner ever. I updated to Sonoma about a week and a half ago.
Odd though, I went to check the syncing folder and when I clicked reveal in finder I could see ll the folders and `workflows\...\info.plist` which had my missing workflow in it.
Then I went back to preferences and my workflow had re-appeared.
I am pointing the sync to a folder my iCloud document folder. I think maybe iCloud had removed the local file for some reason and opening it forced a download and everything started working again.