I suppose whatever you send to Spotify will then compress more the tape compression making it sound worse? Also reminded of that recent thing about AI improving YouTube videos. I wonder if Spotify would do that about certain things - small creators, concerts, other live performances.

At any rate I don't think Master - Tape - Spotify would be likely to sound better than just Master - Spotify.

Spotify itself does not compress luckily. They just do loudness normalization, which does not affect the audio quality in itself.

But the codec used for streaming does some quality degradation that is for sure.

So yeah, it is always better to listen to CD, Tape or what not then to some streaming codec music.