I can´t update my cellphone.

I have a Samsung S20 Ultra 5g, which is an american mobile, i currently live in Mexico and recently my camera is not working and it is a software problem, the solution that i think can work is updating my cellphone to the latest android and UI (i currently have android 10) and i can´t update it because the cellphone is american and i live in Mexico and use a mexican telephone company.

I need to know how can i update my cellphone without having to use external programs or if someone can help me to fix my camera issue.

The model of my cellphone is SM-G988U

Thanks and sorry for my english.