Notes not syncing on 2019 MacBook Pro

The first user account is corrupted if notes don't sync in it , switch to new admin account Set up users, guests and groups on Mac - Apple Support

Make sure all applications are synced in first admin account Turn iCloud features on or off - Apple Support

The desktops and documents must be checked Use iCloud Drive to store documents on your Mac and iOS devices - Apple Support

You must be using an IMAP account Add or remove email accounts in Mail on Mac - Apple Support

The photo library and its preferences must be set up Set up and use iCloud Photos - Apple Support

Change preferences in Photos on Mac - Apple Support

System Photo Library overview for Photos on Mac - Apple Support

The complete application data that are synced with icloud will sync when Mac is connected with high network speed .

Once you are sure all iCloud data is synced delete the first corrupted admin account .

If the problem is still there, try booting into the Safe Mode using your normal account.  Disconnect all peripherals except those needed for the test. Shut down the computer and then power it back up after waiting 10 seconds. Immediately after hearing the startup chime, hold down the shift key and continue to hold it until the gray Apple icon and a progress bar appear. The boot up is significantly slower than normal. This will reset some caches, forces a directory check, and disables all startup and login items, among other things. When you reboot normally, the initial reboot may be slower than normal. If the system operates normally, there may be 3rd party applications which are causing a problem. Try deleting/disabling the third party applications after a restart by using the application un-installer or by using the developer’s uninstall instructions. For each disable/delete, you will need to restart if you don't do them all at once. 

Safe Mode - About.    

If it works in the Safe Mode, try running this program when booted normally and then copy and paste the output in a reply. The program was created by Etresoft, a frequent contributor.  Please use copy and paste as screen shots can be hard to read. Click “Share Report” button in the toolbar, select “Copy to Clipboard” and then paste into a reply. This will show what is running on your computer. No personal information is shown. If the log won’t post, try posting it in Pastebin and provide a link in a reply. After pasting the report in a PasteBin page, go to the top of the page, and copy the address in the URL bar. Paste that in a new reply.        Pastebin

https://etrecheck.com

Hello ScreenShotMeDown,

Thanks for posting in Apple Support Communities!

We see that you are not able to sync your Notes through iCloud on your new Mac.

We’d be happy to help you!

Since the issue is not occurring with the test user you made, there may be an issue with one of the settings on your main user account.

You can follow the steps in Remove login items to resolve startup problems on your Mac to see if that may be contributing.

If the issue persists, contacting Apple Support is the best way to troubleshoot further with the issue being narrowed down to Notes working in the test user.

Take care.