Eventually got it to work by doing this
```
mamba create -n metaphlan -y python=3.11 pip
conda activate metaphlan
pip install -U pip wheel
pip install metaphlan==4.2.3
```
what worked for me is not specifying the python version or putting metaphlan before python because that affects the way Conda starts the dependency resolution process.
e.g. conda create -n metaphlan -c conda-forge -c bioconda metaphlan=4.2.3