The best way to promote yourself is to find other producers and DJs you're into who have some sort of reach and hope that they play it, others will follow suit once that happens.
Presentation is also really important. You can take any mellow house record off Beatport, stick some tasteful artwork on it and call the tracks "studies" or whatever and it will instantly go up in people's estimations despite being the exact same record. It's lame, but that's the way a lot of people think. What you do around the music and how you frame it is sadly more important than the music these days.
The paid reach stuff on social media is a scam, paying for Facebook to reach a larger audience and all that. They artificially inflate the figures to make people believe that they're getting more authentic engagements than they are, it's all fake sites, clickfarms and so on. You're paying for bots and racks of smartphones to look at your page, not real people who might make up an actual audience.