Weird Ingame Lags/Fps Drops

Hey guys id like to ask some questions here since noone seems to reply to me when i sent my ticket, im dealing with some weird issue since the 9.1 patch so lemme explain, at arround 10 minutes the game becames laggy af and my fps drops significantly and it doesnt seem to respond to any of my comands i imput by using my keyboard but it does register mouse clicks, so for example i press tab and 5 seconds later tabs shows up i changed my keyboard and i stil lhave the issue i think there is a big packet lost in this patch and i can asure u im not the only one occuring this weird thing. First of all i called my provider to check if everything is okay at their end and they said it is. I even asked them can they reboot my connection and they did and still it didnt helped, then i repatched the league and the issue was still there and then i decided to completly uinstall and reinstall the game and i still occure the same issue, i never have this kind of problem with other games aka Cs Go, Dota, Overwatch etc but with league hmm i cant rly tell what is going one,im apologise for my bad english i would apreciate any type of help guys, tnx for reading have a good day!