Samsung S20 FE Shows Text Messages are Sent but others not always receiving them

Question

AT&T support did not correct this issue.  I have been having issues with others not receiving my text and picture messages.  This seems to fail the most between this phone an my wife's iPhone 12 Pro that is only a few days old.  However, another regular text was not received by a non-At&T Android phone as well.  At first I thought Google Messages was the culprit because some of my text messages were not being delivered to others.  Then, I uninstalled and tried the built-in Samsung Messaging app.  With Advanced Messaging 'On' my wife will intermittently get photos texted to her.  Sometimes a photo goes through and sometimes nothing.  When I try to send more than 1 photo at a time then only 1 or 0 photos are received even though my phones says 'sent'.  What is going on?  This is 2020 and I shouldn't have a problem with text.  So, I reinstalled Google Messages which I believe only uses MMS and now the pictures are going through.  Is there an issue with Advanced Messaging and sending to iPhones or other phones that don't support advanced messaging?

GLIMMERMAN76 · Answer

There is a issue with advance messages and that phone I read somewhere.  Turn off advance messages and see what happens.

MikeS3000 · Answer

That is exactly what I tried 30 minutes ago.&n(Edited per community guidelines)p; AT&t cloud messages backup started downloading a bunch of missed texts from a week ago!&n(Edited per community guidelines)p; Going to try this.&n(Edited per community guidelines)p; Total (Edited per community guidelines) that I have to do this and reps have no clue.

(edited)