In short: Install sage from conda-forge.
Download the latest release of Mambaforge, take the x86_64 one since not everything is packaged for ARM yet
Install Mambaforge, i.e., open a Terminal, cd Downloads and sh Mambaforge-MacOSX-x86_64.sh
Create a "sage" environment and pick a version of SageMath, i.e., open a new terminal and mamba create -n sage sage=9.2
The packages necessary to run sage are developed on the github pages of conda-forge. The actual sage package and many of its dependencies are maintained by Isuru Fernando (and a few volunteers).
Conda for Sage Developers
You can develop Sage without building any of its dependencies (experimental). On my machine this takes 5 minutes:
$ export SAGE_NUM_THREADS=24 $ conda install mamba $ mamba create -n sage-build sage boost-cpp $ conda activate sage-build $ mamba uninstall --force sagelib $ ./configure --prefix=$CONDA_PREFIX $ cd src $ python setup.py install $ sage -c 'print(version())' SageMath version 9.2, Release Date: 2020-10-24
To check whether there are known issues with Conda:
There is likely not going to be a working package in the near future, see https://groups.google.com/d/msg/sage-devel/wyaV8x5qolI/jVS4DKBvCAAJ.