Spotify and iCloud

Hi👋. I’m using and iPhone 6 with 32GB. I download my Spotify music to listen when I’m offline. But I didn’t really have much space left on my phone so I wanted to use iCloud and upgraded to a 50GB storage plan. But I still can’t use my iCloud space for my downloaded Spotify songs. Can someone please help me? How can I use my iCloud storage for my downloaded Spotify music? (Spotify uses 10GB space on my phone and I want it to use space from my iCloud storage).