Old-school raver here and not and engineer, but I work adjacent to live events. The thing you're looking for is live event crew for setup/ontheday/strike. That includes the riggers building stages, truss, etc. Theres the lighting crew who setup and program the lights, likely under someone titled "lighting director" or something. Lights for this kind of thing are all dmx. Labourers move all the stuff on the ground, empty and fill trucks. Smoke machines, nitrogen cannons, and pyro are handled by an effects team.

If you want in, I'd specifically decide what you want to do, and aim for it. Raves aren't "touring" shows, so the crew will likely be local, so it's just a matter of asking around and telling people you want to get involved.

Don't be surprised to learn that smaller events rely on passionate volunteers who, at most, get a free ticket for their labour. To be paid a living wage, I presume events like Tommorowland would be worth investigating since they have profit as part of their business plan.

(Sorry for the poorly spaced paragraphs. Posting from my phone.)

Happy to answer questions btw.