There is some literature for you to read:

The History of Don Quixote, Volume 1 - Miguel de Cervantes Saavedra
The History of Don Quixote, Volume 2 - Miguel de Cervantes Saavedra
Orlando furioso - Ludovico Ariosto
Book of the Knights of the Brotherhood of Santiago
Roman de Brut - Vace
Erec et Enide - Chrétien de Troyes
Cligés - Chrétien de Troyes
Tristan & Yseult - Eilhart von Oberge
Yvain, le Chevalier au Lion - Chrétien de Troyes
Lancelot, le Chevalier de la Charrette - Chrétien de Troyes
Perceval, le Conte du Graal - Chrétien de Troyes
Li Biaus Desconneus - Renaut de Beaujeu
Perceval - Wolfram von Eschenbach
Meraugis de Portlesguez - Raol de Houdan
La vengeance Raguidel - Raol de Houdan
L’âtre périlleux
Fearghus Mac Róich - Guillaume Leclerc
La Demoiselle à la Mule - Païen de Maisières
Lancelot-Graal, Lancelot en prose, Vulgate
Sir Gawain and the Green Knight
Le Morte d’Arthur - Sir Thomas Malory
Roman d'Alexandre
Roman d'Enéas
Aenēis - Vergilius
Aucassin et Nicolette
Galeran de Bretagne - Jean Renart
Milvinae - Jean Renart
Le Roman de la Rose, ou Guillaume de Dôle - Jean Renart
Le Roman de la Violette ou de Gerart de Nevers, Livre de Gerart comte de Nevers - Gerbert de Montreuil
La Fille du Comte de Pontieu
Jehan et Blonde - Philippe de Rémi
Le Roman de Châtelain de Couci - Jackmes
Pierre de Provence et la belle Maguelonne
Histoire et plaisante chronique du petit Jehan de Saintre et de la dame des Belles-Cousines - Antoine de la Sale
Le roman de Jehan de Paris

I think you can handle this much if you really want to Don Quixote all over the place

Duolingo is actually ♥♥♥♥ for learning something well, so we're going to use old-fashioned method that my grandpa used:

• Pick some cool spanish words like "mierda" or "jodido" or "maricón" or some other ♥♥♥♥, it doesn't matter
  
• Google some grammar rules and try to form a sentence with your words
  
• Use any TTS to know how your sentence is pronounced
  
• Go to any spanish discord server and read your sentence in any voice channel
  
• You will understand very fast was you right or not

Now go to any english discord server and test your new skills there

Go make world a better place, justice is now yours weapon