daffy I used https://play.google.com/store/apps/details?id=com.riteshsahu.SMSBackupRestore many times in the past to create backup of phone calls and SMS specifically and restore on another phone.
Note that GrapheneOS will not give you an option to import things with cable, so you'll likely need to do that with stock ROM, create backup with above app or similar and then import once GrapheneOS is install.
Google backups are not supported on GrapheneOS, so you'll need to use other tools and save backups into files you can transfer back on OS re-installation.