How to access old iTunes account?

I have a vast library on my old iPod but when I got an iPhone, all it has now is “Apple Music”?

I don’t want to pay for a monthly service to access songs I already paid for. Fairly irritated 😠 😣

How can I access my iTunes account on my iPhone? Articles online are insisting Apple didn’t just screw us out of our old music libraries, and it still exists, but I can’t find an article that can provide info on how to get to it