My Mac started typing the wrong symbols

Hi all!

Yesterday my Mac was working fine. My keyboard is a spanish one and I already check the settings, it is supposedly to be the right one, but it is not working properly. alt + 2 should be @, but instead it types ". Also shift+2 gives the same " outcome. How can I fix it? I want that my keyboard corresponds exactly to what I type, and it seems that the configuration is not helping. What worries me the most, is that I did not do ANYHTING and it changed form one day to another.

My Mac is 128 GB, that's why I haven't upgraded from Catalina to Big Sur

Thanks!