The photos disappeared automatically after the update (for the summer of 2021). iCloud storage is full. Is it possible to upload photos without buying icloud ?

If your iCloud storage is full, you cannot upload anything. You also cannot get nor send iCloud emails. You either need to subscribe for more iCloud storage, or delete material to free up space in your current storage plan.

If you don't have a backup or you weren't actively using one, how do you expect to retrieve anything if its lost? Where would you expect to be able to upload anything if you have missing content. You may need to reword your request as there is not a lot of sense to be had in it.