Hi,
This looks related with macOS 26 changes in frameworks. UI pack was tested against macOS 15.5 (the one available at launch, also in D13 launch), and with 15.5 it compiles correctly, but fails in 26.
To fix it, you will need to manually add AVRouting to the SDK.
In Delphi, go to Tools->Options and select Deployment->SDK Manager
There, select the macOS 26 sdk (1) and press the "Add new path item" (2):
After that, write $(SDKROOT)/System/Library/Frameworks in the "Path on remote machine" and "AVRouting" in "Framework name":
After that try reinstalling (you can just write tms build -full in the command line, or use whatever gui you prefer). I tried it here, and while I originally got the same error as you, after adding the AVRouting framework it compiles correctly
[EDIT] As mentioned below in this thread, don't forget to click "Update local cache" once you added the framework!