Same problem. Were you able to find a solution?

I also faced such a problem for the SwiftMessages library, which is simply present in the local SPM framework. Appeared only on XCode 13 beta 3, before that on XCode 12 everything works fine.

5 years have passed, but the problem is still relevant (Xcode 12.4). As a temporary solution, Xcode has to be closed completely. After that, the project is re-indexed and there is enough memory to rename 2-3 classes, after which the action has to be repeated.