If you search the forum you'll find that you can simply set up your M1/M2 Mac to run Rosetta, which will run your Intel based code just fine.
Here is one example post.
In fact, you can take an example from the QIIME 2 install instructions for ARM / Apple silicon. You should be able to do something like this:
CONDA_SUBDIR=osx-64 conda env create -n picrust2
conda activate picrust2
conda install -c bioconda picrust2
conda config --env --set subdir osx-64
I've not tried the above, so perhaps someone else can correct me if I'm wrong.
Even simpler, install the Intel version of conda but make sure your terminal is set to run under Rosetta. You can do this by right-clicking on the terminal and then selecting "Get Info", then check the Rosetta box. Although this assumes you won't need to use ARM based code.