@Morlacchimax !
If storage on your phone is full then you need clean/delete your cache . Deleting your cache will be deleted your downloads too.
From Deezer support page ➡ How Delete your Cache ⬇
Delete your cache
If Deezer is being slow or says your storage is full, this is likely because the cache in the app is full. You can delete the cache, but remember it will delete your downloads, too.
To delete the app cache:
- Go to Settings

- Select Data and storage

- Under Disk usage, Select Clear all
Tip: For ways around this, and to make your cache size less of a problem, have a look at our Smart Cache article.
here is link
https://support.deezer.com/hc/en-gb/articles/115004368825-Problems-With-Playing-Music-On-Mobile
When you Delete your cache if playlists are still there that is mean they was not downloaded .
If playlist are not downloaded you need unfavorite them on your device one by one by click on purple heart .