Jerónimo Tristante is a Spanish author of historical novels. In a video chat held in Spanish (text here) he said (my translation):
Will your novels be translated into English?
I have no information about that at present. It’s a complicated move because a European publisher reads in any language: English, Spanish, French etc. but English-language publishers only do so in English, which means that it’s a big leap because translating a work without knowing whether you will get it published is very expensive and uncertain, so that at the moment it is a wall that many Spanish authors find it difficult to cross.
This is something that I knew nothing about, and it is very worrying. I knew that there was little publication in English of works written other languages but didn’t know that publishers wouldn’t even consider them without setting up a Catch 22 situation.