I usually get over 150 FPS. Idk if its because of my PC or what but even standing still at the base, my FPS dropped and the whole screen lag.
I usually load in fast too, but now it takes much longer.
I know its not my internet or my PC because I've played game like CSGO, Squad, heroes of the storm and its not lagging for me. Its only lagging in league of legends
I have also tried PBE and it work fine there.