As of v0.16.21, the official awscrt ships musllinux wheels. The -f argument to pip can be removed if you install the latest version. This repository will still live in case one needs musllinux wheels of older versions.
Currently the official awscrt doesn't provide binary wheels for musllinux like Alpine, this repository builds musllinux wheels periodically as the awscrt version updated.
pip install awscrt -f https://qqaatw.github.io/aws-crt-python-musllinux/