I don’t know what 75 kbps opus sounds like, but I can tell you how 32 kbps sounds. Versus mp3 at that bitrate, it sounds actually listenable, while mp3 sounds like you’re underwater.

All things considered, the Spotify songs probably sound fine at 75.

It’s the fourth in Z tier

Personally, I’ve had great success with nmac.to Quite a lot of software is available, and I definitely recommend trying it out!