I think that Smart Switch backs up Notes, but if you want to be absolutely sure, you could always connect your phone to your computer & copy them to a new folder on your computer.
If you had enable the option to sync your Notes on Samsung's Cloud AND on Microsoft's OneNote you haven't loose your Samsung's Notes...
To get them , just connect yourself on www.outlook.com with your favorite browser and sign-in. It will bring you on the website of outlook (picture one) to retrieve ALL of your Notes there.. You need to stay on Browser... don't use outlook application...
When you are connected, click on the big N like on my printscreen and you will see your Notes there
I guess that Samsung thought it wasn't worth it for them, or they made a deal with Microsoft that was more in line with their objectives?
You can migrate what you have stored on Samsung Cloud to Microsoft's One Drive.
I enabled Sync with Samsung Cloud under Samsung Note settings. All your Notes will able to restore after factory reset or change phone.
But I also use SmartSwitch to do full backup every 2 months so that all my stuff can be restored without internet and I can pick what needs to restore.
You can use Smart Switch to transfer your data etc to a new phone, or to backup your phone, or to even download OTA updates.
I use the mobile version of Smart Switch to backup my device to the external sd card.