Hello @Thiaagoo
Mixes, including Discovery Monday and Daily Mixes, require input from you via your listening and use of the service. I also recommend you favorite songs, artists, albums, and playlists, as well as creating your own playlists. This will also help to populate and shape your Flow, which is one of the service’s best (if not the best) features.
Opinions on the UI are mixed, as they are with every service. I don’t spend much time with it, I mostly just get music started and spend my time listening. That said, I still find it vastly superior to many other services; the fake, “darkly brooding” Tidal, the way-too-Amazon-looking Amazon Music, and the utterly chaotic Spotify, just to name a few.
Welcome to Deezer and give it some time to get rolling.
Hi @Thiaagoo, Welcome to Deezer! It's great to have you here. 
I understand your concerns and would be happy to help clarify a few things.
As a new user, it might take some time for the algorithms to fully understand your preferences and provide you with the most tailored recommendations as mention by our Super user @GropplerZorn .
Regarding the Monday Discovery mix, Deezer offers a variety of personalized playlists like Flow, which adapts to your listening habits, and your Daily Mixes, which offer fresh suggestions based on what you like. It’s possible that the Discovery mix hasn’t populated for you yet, but keep exploring and the app should start serving more personalized content soon.
As for recommended albums or tracks, Deezer does have these features. You can find them in the “Explore” section or under “For You” once the app gets a better understanding of your musical tastes.
Your comments about the playlist art and the need to dig deeper for interesting playlists are noted.
We're always working on improving our UX and curating better content for our users.
Thank you for giving Deezer a chance, and I hope you continue to explore and enjoy all it has to offer.
If you have any more questions or need further help, feel free to ask.
Happy listening! 
