The Onyx Boox Note 5 is the successor of the Note 3. The upgrades are minor which include Android 11 and G-Sensor. The other specs such as Ram and Storage remain the same.
If you’re planning to buy one then Note 5 will be preferable over the 3 but not worth upgrading if you already have the latter.
You can find the specifications of the Note 5 in the table below-