I had the same issue recently with homebrew and libreadline.7.x.dylib / libreadline.6.x.dylib
I solved it by running:
ln -s /usr/local/opt/readline/lib/libreadline.7.0.dylib /usr/local/opt/readline/lib/libreadline.6.dylib
source: https://github.com/rails/rails/issues/26658