To be entirely honest, I'm quite concerned about your choice on choosing Alpine as the base distro. Their choice of using musl over glibc might be cool but if you have to put old libs inside a container, it's hell (if not entirely incompatible).
The use of musl on the host, outside the container, has absolutely no impact on the choice of libc inside the container. The team chose alpine because it's lightweight, well-maintained and security-oriented. You are free to use any distro you want inside the container, and that will never change.
apologies, you are absolutely right. Has been a very long day :)