Problem confirmed here. Might it be that the package maintainer removed
the 'datafiles/assets' subdirectory, thinking "we're not in the business
of distributing clip art" without realizing that starting from Blender
4.3, really essential stuff (like the sculpting brushes) has been moved
there? See:
https://developer.blender.org/docs/release_notes/4.3/sculpt/
FWIW, here are some other places where people have complained about this
problem in Trixie:
https://www.reddit.com/r/blenderhelp/comments/1hrxu8n/tools_in_sculpt_mode_suddenly_changed_cant_access/
https://www.reddit.com/r/blenderhelp/comments/1iifxz9/all_sculpting_brushes_disappeared_in_version_432/
https://blenderartists.org/t/essentials-asset-library-fully-missing-debian-sid/1577011
