Hi Natw77,
Thanks for your post! I understand when you restart your iPhone XR, old text messages will appear as the latest chronologically. If you haven't already, perform any iOS updates available.
Update your iPhone, iPad, or iPod touch
If the issue persists, I suggest you sync important information to iCloud, then erase your device and then set up the device as new, without restoring from a backup.
You can use iCloud to save your photos and messages:
Set up and use iCloud Photos
Keep all your messages in iCloud
Turn on anything else you need in Settings > tap [your name] > iCloud, then erase your iPhone.
How to erase your iPhone, iPad, or iPod touch
After erase, set up your iPhone as new:
Set up your iPhone, iPad, or iPod touch
Remember, step 5, select "Don't Transfer Apps & Data"
You will need to re-download your apps again, and change any settings you customized previously.
Redownload apps, music, movies, TV shows, and books
Let us know what you find out!
Take care!