Has anyone ever dealt with this error before.

Sounds like perhaps you are either missing a package or a package is corrupted in some way because onRequestRebuild definitely exists.

Note that this identifier is ONLY available in the editor, so any uses of it should be guarded with #if UNITY_EDITOR

Extra unwanted packages in new projects (collab, testing, rider and other junk):

About the fastest way I have found to make a project and avoid all this noise is to create the project, then as soon as you see the files appear, FORCE-STOP (hard-kill) Unity (with the Activity Manager or Task Manager), then go hand-edit the Packages/manifest.json file as outlined in the above post, then reopen Unity.

Sometimes the package system gets borked from all this unnecessary churn and requires the package cache to be cleared: