High Ping always after 2 games

Hey Community, I'm playing on the NA server but im from EU since all my friends come from NA. That ill have a higher ping there and a small delay is for sure n i accepted that. However always after i played 2 games with my friends my ping rizes from 130 ms (which is fine) to 156 ms (which issnt anymore since my game lags with skillshots and so on for like 2 second and i cant really see where skillshots go or my character is moonwalking or csing is a struggle since i sometimes cant see the auto attack). Since im a student and i live in a drom at the university i play there too and my ping is stable at less than 130 ms but always at home it always goes up after 2 games. I can restart the client and again all is fine and then again after 2 games its up to 156 again. I tried the Hextech tool and other solutions like VPN and Proxy off but nothing helps and it seemed very strange that its always after 2 games with fine ping and then all the sudden its not okay anymore. Could also just be the Net Provider issue but wanted to see here if someone had or has the same issues. Also this is only since a few months that this happened. Before all was fine too.