Storing Music Files locally on iphone

I have been using iTunes as my favourite and only Music Library for many years. Also I habe been storing music files locally on iPod or iPhones, by synchronizing with iTunes.

Since using Apple Music, synchronizing has become a night mare. As far as I understand, the logic ist that local storage or synchronizing is not possible is not necessary and therefore not possible because one can play the music online. For me having the files available offline on my iPhone 8 is essential.

I understand that I can download album by album manually in the Music App on the iPhone. That is off course an impossible process as I have 2500 albums. I do need the automated synchronization in iTunes.

Do i have to cancel the Apple Music Service in order to achieve offline storage or is there any other way of doing it?

Thank you.