MacOS Catalina, ruby bad interpreter error

from blog Muffin Man, | ↗ original
Another Catalina rant, this time about Ruby. As far as I know, on MacOS, it is advisable to leave system Ruby version to the OS (For example users don't have write permission on the system's gems folder.) , and install a separate version for development. I had one installed via Homebrew, and never had any issues with it. But after Catalina...