Witch 4.3.6 is out today, and the big change is that it properly ignores windows in Big Sur that aren’t really windows—so you won’t see any more entries for Item-0 or Control Center.
Note: If you used the workaround from our Big Sur compatibility report, you can remove those entries from the Advanced pane after updating.
There are a couple other minor changes you can read about on the Witch release notes page, but the Big Sur fix is the main change.
Updates available within the app, or by downloading a new copy of the preference pane from the Witch page.