performance issue on android devices unity 2018.1.1f1

i'm working on a game, everything works fine on editor but when i test my game on device it lags and not on a specific place in environment or time but randomly i have tried almost everything that i can possibly try, cache referencing on start, controlling garbage collection, minimum use of unity's expensive API calls, graphics optimization, quality settings to minimum, baked light basically everything but nothing seems to be working. even profiler is showing a balanced distribution of load on rendering, physics and other things. tried deleting my libraries and import project again but nothing now i'm out of random guesses as well, any help would be appreciated