SMS Question (Archive / Backup)

[JL Fitzpatrick]

LG V20 / Android 7. Been trying different SMS Apps, current default is Pulse which I like. Also have Textra and stock App. Noticed today all conversations with my wife prior to last Friday are gone, previously backed up last 4 years worth and transferred to this phone in January. Pulse developer quickly responded and suggested I clear App data and reload messages but they're still missing. But they're all visible in Textra (not default). Tried SMS Backup & Restore and viewed the backup but also missing in Backup. So I assumed it only backs up the Default SMS. Concerned if I make Textra the default to back up will that delete the prior conversations too? How do I safely back up all SMS from Textra to reload entire messages and preserve. Pulse developer mentioned I might have swiped by mistake, but never saw a warning to delete. Noticed swipe to delete option is On by default, I've since switched it off.