Have you customized your touch keyboard at all? You can resize and move it to fit your hands/thumbs. You may even prefer a transparent floating keyboard for some situations, like entering text in a wide-screen game on the outside screen, so the game isn't cut off to like 10% of the height of the screen. And that's just the built-in keyboard. If you go third party there are tons of options.

And if you find yourself accidentally adding letters here and there, you can add a 0.01 second hold time before a key is pressed. Low enough that you'll never have to think about it when actually typing something but high enough to ignore most accidental presses. Also if extra inputs happen without you noticing them and you have to go back and fix them when you do spot them, crank your haptic feedback up higher. Won't miss an accidental press then.

One of the main upsides of Android phones is that you have the ability to spend 30 minutes in the options menu of one tiny element of your phone experience. The default settings work for alot of people, but if they don't work for you, change them.