My Samsung A53 died unexpectedly. I have a new Samsung phone and have re-installed my Samsung Notes app but all my Notes have disappeared and there does not seem to be an option to synch the app with my Samsung Cloud
Usually auto sync happens on wifi, whether on cloud or across devices that's if the options where turned on....
In notes to sync open notes>go to the three line option on your left>go to the settings icon in there, you should find those options you are looking for.
Also if you have you old device just make use of smart switch to transfer data...
