CPU bound for Android

Hi guys,
i am developing 2d platform game,i just start optimization process for the game i noticed sometime the fps drop to 40 so i check stat game, unit graph etc
i think i am in CPU Bound but i don’t know which BP cause that.
does number of BP draw calls affect the performance on mobile.
general technical information about the game:
1- i don’t use any post-process.
2- no lights at all.
3-unlit material for everything.
4- i used sprites and flip-book for pixel component
5- using AI sensing for some enemies and nave-mesh bound volume as well.
6- i don’t use mobile HDR so the game is LDR.
7- split the the levels into pieces so i use level stream not load or unload just for visibility.
8- i used event tick for some of BP, for instance Parallax Background.
also i notice in the beginning of the game the curve is very high then becomes spikes till become normal curve.
is there any method to check whats the reason of that , i used Session Front Endbut anything else more simpler.
appreciate your help and advice.

here is some screenshots: