This could be settings messed up after update for your Carrier.
Check if your carrier have iPhone settings for mms on their site, then you might have to correct / type them manually and perform a phone restart
MMS settings had to be typed in:
Settings app > Cellular > Cellular Network Data
You could also use “Reset Settings” on this page but make a screenshot before
In the past I had to set manually settings for my carrier “Plus GSM” in Poland because it was not provided in Apple accepted way (so only iPhones had this isssue) and some updates have either erased it or modified - mostly mms address or max size. Was fixed after some major release of iOS and never after that had problems.