Sagemath kernel not loading in sage compiled jupyter

[irrational numbers]

(many details excluded due to message limit) When I load a notebook, only python3 kernel is available - sagemath kernel is not.

From sage CLI:

sage: from sage.repl.ipython_kernel.install import have_prerequisites

sage: have_prerequisites()
True 

jupyter kernelspec install --user /home/user/lib/sage/local/var/lib/sage/venv-python3.9/
[InstallKernelSpec] Installed kernelspec venv-python3.9 in /home/user/.local/share/jupyter/kernels/venv-python3.9