The source found that the Samsung Cloud service, which allowed, among other things, to synchronize Samsung keyboard user settings and saved words between several Samsung mobile devices, no longer provides this feature.
For some reason, the manufacturer removed the ability to synchronize keyboard data through a proprietary cloud. That is, now, when switching to a new Galaxy smartphone or tablet from an old Galaxy device and using a Samsung keyboard, you will have to manually configure its parameters, add all saved words and wait until the program re-examines your input features in order to correctly predict it.
The source suggests that this is a limitation of One UI 2.1. In any case, he noticed that the option to synchronize keyboard data is absent on devices with One UI 2.1. He turned to Samsung for an explanation and is waiting for an answer, hoping that the restriction is temporary.