Who I have the same questioned this topic

I have gone to the store, spent an hour on the phone with tech support (which were completely baffled) , and all they could do is say an "engineer" would be contacting me in the next 2-3 business days. 
Literally every single thing works I can receive picture messages and group text but will not send them. 

Phone: Galaxy S10 (factory unlocked)
Android version: 9