You can always use a Connect‑IQ watch face on your FR235 instead of the factory-installed Digital watch face. Whether the selected watch face shows you those information items legibly from your perspective and/or offer a font boost option is up to its developer.
Based on what you want to see "large", check out the store link in my sig. If you want to see a very large time, "Simple big". Large time/HR/steps, "Simple Heart", etc.