not receiving texts sporadically

This sucks how as tech upgrades, bumps and anomalies happen to us from time to time.  Started having similar issues with a tmobile locked samsung not sending through to certain iphones.  Sent from what I see, no error (though on occasion with poor signal would encounter).  Recipient screenshot shows none of my messages were received.  But I receive theirs with seemingly little effort.

I started with restart (rarely do, not a good habit tbh), no change. Coincidentally happened just before a mandatory software update reminder, so thought it could be that. Nope, still occurs.  Thought it was wi-fi or cellular-sig related...tried both, nope.

Skipped customer care.  Previous experiences not as helpful and not an option for most to factory reset when unbacked gigs of files exist on the device.  Need to try another method.

Started perusing faq and q&a posts online.  Read about certain setting adjustments.  Nope, either correctly set or no effect after (ex. Message app cache clearing).  

Read about message apps being perhaps out of sync or incompatible.  So I thought about trial installation of a trusted messaging app.  Went with Messenger SMS and installed as default off the google play store.

Despite the annoyance of occasional ads, texting functionality as of this date has been restored.  No missed texts to family and way less confusion.  I'll take the ads gladly over frustrated communication of everyday and important messages.

Perhaps some samsung factory message apps start to show incompatibility with message delivery to apple user devices over time.

Would try this method before switching carriers. Goes without mentioning that problem-free operation is not guaranteed and can still recur as technology shifts regardless of network or phones.

 These experiences unfortunately have finally pushed me to start researching alternative carriers for more reliable outcomes.