Beginner DJ Controller. Spotify Midi Sync Aux In Line

I am looking to get into DJing. I don't have preferences for the software, but I would like to DJ from a Spotify Premium sub.

However, ideally I would like to have a midi clock out matched to the beat and an AUX channel input that I can fade in, from some external synths.

It seems that the midi clock requirement and the AUX input limits the selection to mid-tier boxes. Any suggestions?