I had a similar issue when I updated my phone in regards to the Samsung Keyboard @Lido
At first I turned Off Predictive text which returned the typing to normal.
However I ended up resetting the keyboard to default to remedy the situation.
Settings, General Management, Samsung Keyboard Settings , Reset Keyboard.
Regarding the phone lagging etc please try https://www.samsung.com/uk/support/mobile-devices/how-do-i-clear-the-cache-on-my-device/ You may need to hook up to a Computer or insert your earphones to enter into recovery mode.
Daily Driver > Samsung Galaxy s²⁵ Ultra 512Gb ~ Titanium Black.
The advice I offer is my own and does not represent Samsung’s position.
I'm here to help. " This is the way. "
