I tried that, too, many times. Log out and clear local data. Then log in again—still the same result. The data was cut off on Dec 31, 2022.
Those notes are not lost. They are just hidden! If you search by title, you can find the hidden notes. If you click the search result and open the hidden note, it magically gets added back. You can even see an increase of the total number of notes.
So, the notes are synced already because I can search them. As I said, they are just hidden!