1. Please add options to conserve battery too. A FPS limiter would be good. Messing with the system power management when the user doesn't want to be tethered to a wall plug is Not Nice(tm).
2. When you do UI scaling, especially if you're young with 20/20 eyesight, please allow scaling beyond what you think is big enough.
For #2--my glasses prescription is so strong that I spent $330 on fancy lenses today in the hopes that they'll distort less around the edges. Wish me luck. (:
Using Vsync is actually conservative power wise. You can always smash the gpu by rendering frames as fast as possible. This a one way of reducing input latency in FPS shooters, using vsync guarantees one frame of latency on a fast GPU.
2. Agreed 100%. All too frequently the UI is too small on high dpi monitors (see CIV6), or unreadable when viewed from a distance when playing on a TV (see Witcher 3)
It depends on the game. What does Civ need 60 fps for? Not sure if they have a limiter because I'm not playing 6 due to some of their design decisions that tick me off.
On the other hand, I do keep my Minecraft limited to 30 fps.