Obligatory “I don’t know” but dont you typically have to own music used for DJing? Maybe it varies country to country but I’m almost certain that in the US, a subscription to a streaming service doesn’t entitle you to DJ with that music

You can use Audio Hijack Pro to strip DRM from any audio format (there are other options, but that's the one I use and the only one I have any experience with).

You will definitely need to strip the DRM. Alternatively you can "buy" the music in iTunes for 99c per song - those don't have any DRM.

I don't do any DJing, but in live theatre we use QLab for audio playback and I'm sure it would work fine for your use case even though it's not specifically designed for DJ work. Basically put all your audio files in a folder, then create a playlist in QLab - (QLab calls them "Workspaces").

By default, QLab is setup to hit spacebar (or the "GO" button) when you want to start playback on an individual audio file. You can configure it to start the next song when the first one is finished (and you can cross fade them). Read the manual... it's a complex tool with features that can be a little overwhelming at first, but it really is simple and easy to use once you get your head around it.

QLab is free if all you need is stereo audio without any fancy effects/etc. If you want surround sound, video, special effects lighting, smoke machines, etc, then it costs a few dollars per performance (until you've used it 400 times - and then it's free after that).