How do I download music offline?

Which music listening services allow you to download tracks for offline listening without complicated restrictions and additional conditions? Very often, music platforms provide this option only as part of a subscription or with certain limits, for example, by limiting the number of downloaded tracks or requiring a permanent Internet connection to confirm the license. I am interested in whether there are services where you can download music without such restrictions, store it on your device and play it at any time, even if there is no network. It is also important that the downloaded files are not protected by DRM, so that they can be listened to through any application, not just through the official application of the service. Which platforms offer the most convenient and profitable conditions for downloading music?