Hi, couple of options that are only phone setting related and not game related, so you can use your own preferred internet searching app or browser to find other solutions, but these are ones you can try:
1. Turn off predictive text - that line above the keyboard (in your pic it shows "I", "the", "I'm" - on the keyboard, touch and hold the globe icon (under the Z), then Tap Keyboard Settings, then turn Predictive on or off. You can turn it back on again afterwards as it only takes a few seconds to turn that feature on and off. This method definitely works.
these one might work and are only suggestions for you to check for your own device:
2. Adjust the size of your display font - might not make a difference in game but worth a try
3. Check your default keyboard size and type
4. Turn the screen lock on or off depending on your default setting
Removing predictive text should give you extra space to see the line to type on. you might not have the same issue on a neighbour wall than you do on your own. The spacing is different for me depending on whether or not I'm writing on my own wall or a neighbours. Hope that helps a little bit.