I created a new project using LWRP and i immediately tried building it to my phone Huawei Y9 2018 (specs)
With post processing on or off the build still starts with 40 fps and gradually go down to 10 fps within a few seconds.
i tried changing the shaders on all materials to simple Lit as well. there was no change. and i disabled every gameobject on the scene and built again and the empty scene is still running at 24 fps.
then i used the props in the sample scene and made a normal project and added mobile diffuse shaders and the build ran at 40+ fps (No Post processing).
Is it just my phone is under powered or is something wrong with the LWRP sample scene? Thanks in advance