Thank you! I tried creating a new environment using
conda create -c conda-forge -n new_env “pymc>=4”
and the problem persists. After 5 minutes, using the ensemble data above, the samples are 0.28% complete. Neither aesara or theano seems to be installed in this environment. I get the same results on my laptop (Mac Ventura, Apple M2) and a linux box. (And many thanks for your time and your kind response).