Ok, i need to check on this a bit more. It should be available on 7.0. It's possible it was disabled on the Sprint version of the phone. I find more info, I'll post it.
Just to verify, these are the instructions your using?
1. Go to the Settings menu on the Galaxy S7 or S7 edge. 2. Scroll down to Display > tap on Change screen resolution. 3. In here, you can select: HD (1280 × 720), FHD (1920 × 1080), or WQHD (2560 × 1440) 4. Finally, tap on Apply to save the changes.
If my post or someone else's answered your question please mark it an Accepted Solution.
Keep in mind, like you, I am a Sprint subscriber. I am in no way employed by Sprint in any sense. I just know stuff.