Ok, I managed to solve this issue. Problem was I had a Postgre installed (and running automatically) on my Windows and it was listening on the same port of the docker one, so when I was trying to connect to my docker postgres I was actually connecting to my local postgres (that's why credentials were wrong).

I've disabled my local postgres (and set it to not start automatically) and now it "works". I mean, I'm still having troubles (dependencies and plugin conflicat, but at least the worst part seems solved).

Thanks everybody for your help.