The option to enable/disable VSync in options.txt is broken due to RENDERGRAGON. Setting the VSync value to 0 causes extreme input lag, already reported and described in issue MCPE-98861. With that, it is impossible to unlock the frame rate,

Even with VSyinc disabled in options.txt, the framerate always limits to the monitor refresh rate, which in my case is 75hz, so, the FPS won't go past 75FPS

Note: I'm an AMD user, my processor is a Ryzen 3 3200G and the GPU is the Vega 8 integrated one, so things may behave on different CPUs/GPUs.