I remember seeing DJ Armando show up to Medusa’s and play with two turntables and a reel-to-reel.
I used to edit some tracks on older wav editing software, then play them into my set when I used a 4-track recorder to make mixes. I carefully manipulated the pitch control on the recorder to somehow mix it in.
I’ve said before how many DJs in the 90s used ProTools to make mixes, using sequencers, editing, and warping.
This is a redundant point. DJing isn’t just about rotating platters, but about making sets or even music with other pieces of music.