Perhaps the right community for you would be the English language, since you have written in English but in the Spanish community.
Anyway, I write some translated tips 🙂
Check that your iCloud plan has actually gone up to 50 gb. You can see it from the iPhone, General, Storage and iCloud Settings in the iCloud storage section.
If your storage is 50 gb, with the Photo Library activated, iPhone photos will automatically upload to iCloud. It is an automatic process, although it is not immediate and must be over Wi-Fi. The time it takes depends on the volume of data to synchronize and the connection to the internet. It is necessary to have patience, that in the end everything will be synchronized and the system will be normalized.
If your storage is not yet 50 gb, it is possible that the photos could not be saved to iCloud because of lack of space. In that case, contact Apple technical support to inform you of any problems. From this link you can talk to them: https://support.apple.com
You will tell us how you have gone.