I’ve been fighting with the fact that downloaded flatpaks were not in Spanish.
I even opened on downstream issue here, that I recommend you to read because it’s very short: Only English from Flathub (#115) · Issues · GNOME / Clocks · GitLab
Well, after all, I had to do this:
rpm-ostree install langpacks-es systemctl reboot
It seems weird to have to do this because the system was configured in Spanish when I installed it. Am I too ambitious if I expect langpacks to be automatically installed?