Hi,
Kindly note only when you need to see the sticky notes on your favorite devices on the web, you are required to sign in all your device to the same Microsoft account.
If only one device will be used like Windows 10, you don’t need to be signed in to your Microsoft account to start using Sticky Notes. Just start Sticky Notes and starting jotting away. Sticky Notes will open where you left them.
Moreover, it is Microsoft account instead of O365 account that is required to sign in sticky notes.
Hope this helps and please help to accept as Answer if the response is useful.
Thanks,
Jenny