How to reset and clear all my data and preferences of Apple Music and start over again

it sucks not to be able to erase all activities and start from scratch.

my library is since 2015.

Hi senseone,

Welcome to Apple Support Communities. We understand you'd like to clear the recommendations you're seeing from Apple Music. We can help point you in the right direction.

The ability to immediately clear the recommendations you're seeing from Apple Music is unavailable. You can, however; love and dislike the music content you're seeing in Apple Music. This will help improve future recommendations in Apple Music. Here's two helpful articles with more information: Stream recommended songs from Apple Music on Mac and Love or dislike songs in Music on Mac

Kind regards.