Hi, it seems like I solved this problem by downgrading the conda to 23.1.0.
Julia creates its conda env at ~/.julia/conda/3/x86_64/. So what I did was activate this env by conda activate ~/.julia/conda/3/x86_64/. Then manually downgrade the conda version by conda install conda=23.1.0.
After downgrading the conda, I install the matplotlib package by conda install matplotlib.
I hope this works for you.