Final Cut Pro constantly beachballing and hanging at nearly every action

Derek, the spindump indicates that during a blade edit operation, an audio effect initiated a failure cascade that hung the main UI thread. Sequence:

• The operation started as a blade edit (-[TLKSplitItemsHandler splitAtCurrentLocation:])
• This triggered an audio unit effect activation (-[FFAudioUnitEffect effectActivated:])
• The hang occurred during parameter synchronization in AudioUnitGetParameter
• The thread is stuck waiting for a response from an XPC service call (mach_msg2_trap)

Multiple audio processing threads are involved, suggesting a complex audio effect chain. This pattern suggests the hang may be due to one of these scenarios:

1. An audio unit (effect/plugin) is not responding properly during the parameter retrieval
2. There's a deadlock in the audio processing chain during the effect state copying
3. The XPC communication with the audio service is timing out. With Apple Silicon, all third-party plugins must be run in a separate host process and communicate with FCP via XPC calls. This reduces the chance of a buggy plugin crashing/hanging FCP, but does not totally prevent it.
4. Verify you are not running FCP itself in Rosetta2. Some misguided audio Fx vendors have not updated their AU effects to Apple Silicon and have covertly given guidance to customers to run FCP under Rosetta, which enables the use of their x86 plugin without them updating it to Apple Silicon. However, this often results in instability. Use Activity Monitor's CPU tab and examine FCP in the "Kind" column. That should say "Apple", not "Intel."

Suggestions:

• Reboot MacOS -- it's been up for 10 days
• Remove all possible audio effects and examine behavior
• Duplicate the timeline, open the duplicate, select all clips with CMD+A, remove all audio effects with Edit>Remove Attributes>(select effects to remove). Examine behavior.