The learning curve is a bit steep but his guide is awesome https://trash-guides.info/Radarr/Tips/How-to-setup-language-custom-formats/
In the other hand, the public trackers are dominated by English and, at least I, I couldn't find a lot of Spanish dual movies better than the 720p
In any case, if you can gain access for a Spanish private tracker with radarr support, let me know