Your system must meet the minimum specifications to run ERA plug-ins,
Final Cut Pro: 10.4.10, 10.5, 10.5.1, 10.5.2
macOS: 10.14.6, 10.15.7, 11 (Big Sur) * Intel processors only
Note: The Audio Clean-Up Assistant is not yet compatible with Final Cut Pro.
Below is a list of the supported ERA plug-ins for Final Cut Pro.
You can read more about the best practices for audio editing in Final Cut Pro X in our article here.
For more info on how to resolve a crash in Final Cut Pro X you can refer to this article.