I also read only technical books for many years, but then just stopped and donated my entire library to a computer lab that teaches technicians.
I was able to get both books from my local library in digital format for my kindle e-reader. They are unbelievable for reading, no eye strain like a computer monitor or tablet. I could read 10 hours straight with my kindle oasis without eye strain. But check your local library if you decide to read them in either format.
I need to get an e-reader. Currently use an old phone with a 6 in display. I can do black and white and drop the blue light on the display but it still doesn't feel comfortable to the eyes.
Are Kindles tied to Amazon's system? Meaning can I read books I have locally in pdf or epub or only in their format?