I have an extensive history of SMS messages going back to early 2013. However, it's taking up nearly half of my iPhone's storage space and counting. I understand that there's a feature that automatically deletes old messages after a specified period of time, but I'm somewhat put off by the implication that messages deleted in this way won't be recoverable even from iTunes backups. Frankly, I'm sentimental about this (not to mention that I occasionally need to dredge up years-old messages if discussing an old project).
My question is this: is there a way to permanently transfer my huge backlog of text messages onto my Mac, while keeping messages from the last (say) six months on my iPhone for portability's sake? This way, I'd be able to access old messages as needed, while minimizing the amount of iPhone storage space they take up.
I've tried a few third-party utilities (iExplorer, iMazing), but they don't seem to be able to do this kind of thing specifically. I'm working with an iPhone 5S, 14.91 GB, iOS 12.4.5, and an older MacBook Pro running Sierra. Thanks!