How does silent payments work, if I may ask? What is hidden from the rest of the world's view (I.e. those not party to the transaction)

Payjoin = #JustChangeOutputPrivatization? All I want to do is (when it's time to burn the nsec) consolidate all the on-chain zap UTXOs that were ever received into 1 output (where the hygiene starts anew)... no bloody change, ever!