That sounds like a the ear training I have done but even after a couple of decades I don't have any real ability to tell the difference between intervals. For example, I listen to a musical interval and try singing up the major scale to match it but everything matches a fifth (in my internal melody). More recently I found the Sonofield app an interesting idea for learning the intervals but wasn't able to gain any consistency.

I remember many years ago in my music lessons being shocked that some people can hear multiple notes played simultaneously. I've never found much material on learning this skill.