How to recover deleted Apple Music playlists on my MacBook Air

I was on a MacBook Air and think I pressed a shortcut. This deleted my whole playlist with ~900 songs without warning. It had already deleted it from my phone as well before I could get to it. I managed to recover the playlist through a contact because I shared the playlist prior to me deleting it. But, instead of the whole playlist coming back, I only got 450 of the songs back. Does anyone know why this is, and how I can recover my full playlist?

[Re-Titled by Moderator]