Since we can assume that you are editing the text and not much more, you might be better off using an external keyboard. I've put a lot words down at lunch!
I too have issues at times when navigating and making certain text-edits, words, phrasing and such.
Re-pair your Bluetooth keyboard or consider a separate keyboard like a Logitech 480 or other device that can be paired to multiple devices.
Also, if you see something you don't like in your text but will take a big edit, you might make a Note instead of the edit on the phone so when you are on a full-windows device you can make the proper edit.