You have the terrible google background tasks:
[Loaded] com.google.GoogleUpdater.wake.plist (Google LLC - installed 2024-11-20)
Command: ~/Library/Application Support/Google/GoogleUpdater/Current/GoogleUpdater.app/Contents/MacOS/GoogleUpdater --wake-all --enable-logging --vmodule=*/components/update_client/*=2,*/chrome/enterprise_companion/*=2,*/chrome/updater/*=2
[Not Loaded] com.google.keystone.agent.plist (Not signed - installed 2024-01-14)
<Empty>
[Not Loaded] com.google.keystone.xpcservice.plist (Not signed - installed 2024-01-14)
<Empty>
These can cause havoc on video applications, as they hog the system videotoolbox at times.
This seems to be the case, as evidenced by the high cpu use of VTDecoderXPCService
You should not have Chrome on any mac, but at least not on any mac that runs video applications like FCP.
See https://chromeisbad.com for an explanation and for how to remove them. It is NOT enough to trash Chrome, as that would leave these behind.
After that, it is recommended to delete and reinstall FCP - but that is likely to get you 10.8.1 instead of 10.7.1
Also: you have Dropbox. Make sure that any media or library used with FCP is stored locally and is NOT being synced online.