scikit-geometry does not work due to GMP version incompatibility

I am trying to run scikit-geometry (Python 3, Mac OSX, version 10.15) but get an error message due to GMP version incompatibility:

Incompatible library version: _skgeom.cpython-38-darwin.so requires version 15.0.0 or later, but libgmp.10.dylib provides version 14.0.0

This did not help, as the libraries seem to be up to date:

conda install -c anaconda gmp

Nor did the alternatives using brew:

brew upgrade gmp

and

brew reinstall shellcheck

How can I solve this?