” Open up the Settings app, then go to “Cellular,” followed by “Cellular Data Network.” Now, in addition to the four things mentioned before, you’ll want to add “10485760” into the MMS Max Message Size field. And that’s it. Save it by exiting those settings, then restart your iPhone. “
Google updated their recommended settings for iPhones:
https://support.google.com/fi/answer/6205096
I can confirm that this working on my iPhone XS Max. Finally!