I do experience a lower flow pressure after installed PRV.

Statis pressure, yes can maintain at pre-set level.
But once too many valves open at the same time, the pressure drop significantly.

But one good thing about PRV, less need to replace valves from time to time.
Pipe may not leak, as pipe itself withstand much higher pressure than normally water supply if installed properly, but valves do leak, (dripping water a bit even you have close it) as everyday we turn on and off, with high pressure, it wears down valves more quickly, especially those cheap butterfly type of valves, very quickly wear out.