I ran into this issue today (May 2025). I was running Python 3.11, and that it transpires is not compatible with Kepler. Here is my working solution...
conda create -n keplergl_env python=3.9
conda activate keplergl_env
pip install keplergl notebook ipywidgets
python -m ipykernel install --user --name keplergl_env
jupyter notebook
or jupyter lab
(both worked)