Me and few of my friends have this issue. Keyboard predictive word feature isn't working after the latest Android update (about a few days ago...). I am using this feature very often and really on it a lot. I have found some solutions like checking for updates of both keyboard and languages as well as resetting the keyboard to default, I have done it all and it still isn't working. It is definitely due to update so please try to fix this problem.
I've found a solution - I did this in whatsapp and it worked. when keyboard is open, press the three dots, in there you select samsung keyboard. Then it should be automatic. I'm now able to use the predictive text toggle!
I have similar problem. The predictive text does not work after my latest smart switch update. Tried all methods installing un-installing my smart switch app and it still does not work. Went to on-line chat and they advised soft reset. Doesnt work either. Very frustrating! Am using S10+
