"Cellular Update Failed. Your iPhone cannot make and receive calls or access cellular data until it has been updated."

Hi, yesterday my cellular data suddenly stopped working and this message popped up on my screen. "Cellular Update Failed. Your iPhone cannot make and receive calls or access cellular data until it has been updated."

So, I did some digging and found this steps that supposedly helps fixing this exact problem https://support.apple.com/en-us/HT208733

So I plugged my iphone in my mac and tried to update my iOs from my computer but it hasn't worked! And then, I got another error message that said something about the firmware being corrupted (screenshot below)

I would really appreciate someone helping me out here because I've already tried updating the iphone about five times with no luck and it's starting to get really frustrating

Thanks!