FPS Android apk

I have a very complicated problem, that I have been trying to solve it for a long time and I have not been able to do it yet, I have given them my problem ..

The problem is about the performance of the game on the android platform, what happens is that the game works well but only at the beginning ..
after playing a few minutes the fps go down and I can not find any reason, sometimes takes more and sometimes less, sometimes if I close the application and return to enter the fps and return to normal but other times I close it and re-enter and the fps are still low, something also happens when I minimize the application with the option to show open applications on the cell phone, when I do that and go back to the application (without closing it obviously), the fps return to normal but after about seconds already go down again, we must emphasize that this happens only when I create the apk and install it on my cell phone, on my PC everything goes normal and that fps downfall does not happen, I tried to use unity remote but I see that unity remote takes the pc fps and it is not the same.
I also have to emphasize that the application does not have any type of error according to the console ..

If you have any idea that it can be or how I can get to discover what the problem is, please write me here or in private I would really appreciate it.

If you have any doubt or did not understand something tell me since I am using the google translator and I have no idea if they understand.

 

Have you tried to use Unity profiler to figure out what is causing the FPS decrease?
https://docs.unity3d.com/Manual/ProfilerWindow.html

 

This is an issue i have encountered myself.
Haven't figured it out completely yet, but in my case i think it has to with thermal throttling.