Have you considered picking up a Payg sim card for your particular network @Julie84 and use that to see if texts etc work OK ?
If your phone model is an unlocked to all Network's version them try another Network's sim payg card.
This is a good process of elimination to rule out the phone at issue.
Current Phone ~
Samsung Note 20 Ultra 5G SM-N9860_256Gb SnapDragon 865+
Samsung One Ui 3.1/ Android 11.