I can connect to Redis using the public url but I would prefer to use the internal url

I've tried different methods of connecting but nothing works. I am not really sure what is the problem.

According to the docs, family must be set to 0

Have you tried that?

That's only for ioredis

oh, true

i believe it is set to 0 by default on the lib im using

i still couldnt find a way to make it work so I ended up switching to ioredis and it finally worked
not sure whats up with the previous lib i was using

It may have been a super old version that never had support for IPv6.