Related issue: inkscape/inbox#13397 which affects the extensions manager.
The GTK4 typelibs are missing from the bundle. gtk-4 is not built with introspection. The fix is to add -Dintrospection=enabled and a dependency on gobject-introspection.
The python .so files in the bundles (PyGObject, lxml, pycairo) still point to hardcoded paths /Users/Shared/work/jhb-1.2/.... We add ink_relocate_python_libs that scans every .so and .dylib in the bundle and rewrites those paths to point inside the bundle.