No way to backup & restore text messages with AT&T "advanced" messages?

My Samsung S7 was defective, and AT&T sent me a replacement. In the process of transfering all of my content over from my old device to the replacement device (another S7, initally using SmartSwitch), I noticed that very few of my outgoing texts had transferred over. I also tried MyBackup, Carbonite, Helium, AT&T Mobile Setup, MobileTrans ... and kept getting the same result. Upon further investigation, it turns out that the message that would not transfer wer "advanced" messages - a new format that AT&T has started migrating to (but can be disabled). None of the backup softwares on the market work with this format, and the new format has very limited value (with very few users, I see message receipts - that's all I 've noticed different). However, not being able to backup and restore my texts is a major problem for me. I frequently reference past texts, and I've worked hard to keep my full archive through backups and transfers for years. AT&T makes this change, doesn't inform us of the implications, now I'm stuck about to lost important data. I've spent hours with AT&T support in chats, on the phone, in the store, and nobody can help me. This feels completely unacceptable.