SMS history vanished

This morning my entire text history with my spouse going back years vanished. I did literally nothing except open my phone and start sending her a message.

I tried restarting, no luck. Switched to Samsung messages, gone there too. Installed Google Carrier Services, which was NOT installed already even though RCS has been functional this whole time. No change. Updated Google Messages in the Play store, no change.

It was not a wholesale cleanout; I have years of text history for many other contacts, although I cannot say for certain that no other contact's history was affected.

Any suggestions for further debugging/restoration steps I could follow? Thanks in advance for any advice.