As typically Networks don’t keep sms texts on their servers then if a person hasn’t created some form of back up of their information using their Samsung Account or other options then the only option I can think of are looking into the various software options that purport to be able to pull back deleted data.
Current Phone ~
Samsung Note 20 Ultra 5G SM-N9860_256Gb SnapDragon 865+
Samsung One Ui 3.1/ Android 11.
Hi @Bubbles114 just to safe guard future messages you could take screen shots of important messages and you can use the scroll feature that once you have taken the shot in the bottom left you will see the capture more option