Hi BobT1
The way that I have found to do this now is to open the messages app, swipe right on the message header so that you can "pin" the contact to the top of the messaging app. Then, from the icon if you hold/press that then you can delete the conversation. It just says delete, but it does mean “delete the conversation.”
You have to manually go through your messages app in order to do this. Unless you have recently sent a text, they may be buried way down the line but there is no other way to "pin" a contact. Still, this works.
I do not know why the functionality was changed. Apple is limiting our ability to clear information from the device quickly and easily. I wonder if this isn’t a directive passed on by law enforcement/government. A lot of things go into a deleted items section of apps, and then get deleted at a later date. It seems as though we can’t be trusted to choose to delete something permanently by our choosing. Unless you’re aware that there is another background folder in a lot of apps. keeping the deleted information, then normally for 30 days it is still there.
This is my take on why this changed so I’m not certain that I am correct. It is definitely frustrating, and more involved just to delete information. In an app. like notes for example, I CTR+A too select all and press delete when I want to delete a note rather than sending it to another folder to be deleted again at a later date.
I hope that this is helpful to you.