What are you trying to do guy? Be a DJ but you don't have any idea how to be one?
You have your music on a storage device, or streaming source, and you plug it into their system and play..
A DJ typically has their own gear, and just take it and plug into the venue's audio setup.. A ton of clubs today have the Pioneer CDJ+DJM mixer setup, which is pretty much the standard for most pro DJ's, so you would simply bring your laptop and use their with your Serato, if you don't carry your own gear.
YouTube quality is terrible, and it is noticeable to people who enjoy music. Spotify and Apple Music offer better quality, but I believe
Tidal offers lossless streaming. Don't forget if you're trying to play streaming music for a group of people, you're at the mercy of the Internet connection, and you will have pauses and beat matching issues when transitioning to the next song.. I don't think people are going to enjoy your set much tbh