I have the Samsung Fold³ and it works seamlessly.
Samsung sell them via https://www.samsung.com/uk/mobile/
If the phone is lagging when typing then try clearing the keyboards cache and or reset it.
Try another keyboard.
If I can be of any further help then please don't hesitate. Take care. 😎
Daily Driver > Samsung Galaxy s²³ Ultra 512Gb in Phantom Black.
The advice I offer is my own and does not represent Samsung’s position.
I'm here to help. " This is the way. "