Messages set to keep texts forever but still deleted them, is there any way to retrieve them?

Hi, I have always had my messages set to be kept forever, but recently when I went to go search through them for a conversation that was a couple years ago, the texts were gone. They would show up in search, but when I clicked them I would just be taken back to the last message that had been sent to that person instead of the messages I wanted. I then scrolled as far back in the messages to that person as I could, and I wasn't able to even go that far back before they got cut off.

I've been researching this for a few days now, and it seems that what happens is they delete when your storage is too full, which my storage was constantly too full on my old phone (I got a new one a couple months ago), although that is extremely messed up that they don't even warn or tell you that they're going to do that since I would have deleted a bunch of other stuff instead so that I could keep my messages. I don't have any backups from long enough ago to reset my phone too, I don't even have any backups from my old phone since I had to help backup both my parents phones and for some reason, iTunes doesn't keep more than two backups at any time.

However since I can clearly see the texts in the messages search, I just want to know if there's anyway I can retrieve them since that makes it appear like they are not fully gone? I'd appreciate if anyone could help me because this makes me very sad and upset, and I hate that apparently saying "keep forever" does not actually mean that.

My phone is an iPhone 11 Pro, and it sets to the newest update 14.4 with 119 space still left in storage. My old phone was a iPhone 7. Also, I've never used iCloud, so unless it's something that happens automatically without any interference from me, then it's probably not helpful. I think that's all the information you might need, but let me know if there's anything else, and thank you for any help you may be able to provide.