When Proton sends a DJ Mix to Spotify, it will appear at the top of the DJ's artist profile in the "Album" section.
The mix also appears on each of the artist profiles of any artist that has a track featured in the mix -- but for them, the mix is listed at the bottom of their profile in the "Appears On" section.
Here's a screenshot of how an example DJ mix appears on Spotify for DJs (on the left) + featured artists (on the right):
When fans open the mix and view it directly, the DJ will appear at the top of the page as a "Release Level" artist. Below that, every track played by the DJ will appear, correctly linking to each featured artist's official Spotify profile. This helps fan see exactly what song they're listening to in the mix, and can help them discover new artists to follow!
In this way, the DJ Mix is connected to both the DJ's profile on Spotify plus the profiles of all the artists featured by the DJ in the mix. This helps boost exposure for the mix, because Spotify may recommend the mix not only to fans of the DJ, but to any of the artists featured by the DJ too.