Using the guided installation help, the iMac (version Monterey 12.6.3) fails to detect the installed plugin. It locates the file in the Applications folder.
The guided help indicates it should be located on the MacOS at
Users/{username}/Applications/ArduinoCreateAgent
I moved your topic to a more appropriate forum category @griswols.
In the future, please take the time to pick the forum category that best suits the subject of your question. There is an "About the _____ category" topic at the top of each category that explains its purpose.