I'm using Ubuntu on desktop and my phone's an Android.
I'm looking to use the phone's inbuilt keyboard for typing or some programming specific one downloaded from Play Store. I want to type as best as I can using a phone.
I'm thinking about holding the device in both hands and double-thumb typing on it. That doesn't trigger my RSI.
Are you using voice input in your phone, or are you saying the touch keyboard is comfortable for you?
If I had RSI, I wouldn't want to be constantly gripping a device in one hand and tapping at it with another arm. That doesn't help me rest.