Backup does not show messages or contacts
I am backing up my iphone but do not want to sync with icloud - only using icloud for backup. Want to keep the data on the phone and for messages, for example, syncing deletes older messages off the phone, as I understand. Question: when I open backup on my phone, it shows all the apps that are backed up, with a green slider button. It shows photos and lots of apps in the backup list, but messages and contacts are NOT listed in the backup list. I can't check in icloud on the web, because I don't have syncing turned on and don't want to turn it on (so icloud on the web is empty). I know I can turn on syncing for messages, but I don't want to do that. How do I know if my phone has backed up messages and contacts? If they are not on the list (and no option to add them other than syncing, so far as I can see), are they not backed up?
iPhone 8, iOS 16