Not so long ago I searched for a Spanish dub of a very popular anime and had a tough time finding active seeds on most sites listed on the Treasure Trove page.
I think YMMV depending on what you look for, and how old is it. I had much better results adding “Spanish” and “latino” to a simple google search. Turns out some people stream a single series on a website (as opposed to multiple series hosted on large streaming platforms).