Installig fast-jl with Python 3.11 and setuptools==65.5.0 gives:
> pip install fast-jl
...
DEPRECATION: fast-jl is being installed using the legacy 'setup.py install' method, because it does not have a 'pyproject.toml' and the 'wheel' package is not installed. pip 23.1 will enforce this behaviour change. A possible replacement is to enable the '--use-pep517' option. Discussion can be found at https://github.com/pypa/pip/issues/8559
This could be linked to the issues with installing traker[fast] and fast-jl with pip>=23 in #69