The only place I see trusted devices in my Samsung account is in password and security, 2 step verification security settings.
All it does is bypass the 2 step verification security feature for websites that you trust. If you delete them all you will have to use the 2 step verification process again when you sign in to the websites or apps that you deleted.
I would delete them all and use the 2 step verification security for a few days and check to see if any new entries are listed as trusted. If you see new trusted devices listed and you didn't add them I would delete them and change the Samsung account password. Once it's done you can add websites that you trust back to the list.
Thank you for your kind reply I appreciate it.
I agree the delete all page that opens should show a list of everything we've added as a trusted device with an option to remove them individually. It's really not useful if the only option is to delete all.
Let us know if anything shows up as a trusted device without your authorization while you're testing.