The mixes won’t show up by default, but you can save a mix as a playlist from the Tidal interface, and then you should see it as a playlist in Roon. Tidal playlists appear in Roon through a frequent sync (the same way a favourite in Tidal appears as part of your library in Roon).
If you want to force the sync, you can go into Settings/ Services then click the Edit button beside Tidal and you’ll see a Sync Now link:
