What is WaitForTargetFPS in my Profiler is says its using 98- 99% under total?

Unity Limits you Frames Per Second and WaitForTargetFPS tells you how much its limiting. it does this so your 60 or 110 FPS (Frames Per Second) doesn’t use all the memory and go to something like 800. An another example of this on Windows is to go to task manager and sort the process by highest CPU, it likely a lot of its idle and you will see a process called Idle CPU.

you only need 30 Frames per second to trick the eye so using that extra power to go above the target frame limit (usually 60 or 30)is pointless , 60 is usually used for games it might go up to 110 for next gen consoles.