[gameplay] shopping cause lag and high chance of disconnect

I'm a MAC user. I Play as Ryze in PVP and other champions in co-op vs AI. It happen before and after the new 4.18 patch, but gets worse after 10/16. There is a huge delay/ lag to open the shop in game play. It takes 12 second to get the shop open, and 5 second to select the item, and wait another 5 second to buy it. the gameplay freeze at each steps towards buy an item. I clean up my computer have at least 100GB storage and my graphic has turn to low already.

After 25-30 min there is at least 50% chance when I open a shop I will be disconnected completely from the game. I will not be able to reconnect on "Attempting to reconnect". It will freeze there more than 20-30 min. And the game will end before that and I was fear to exit that game to become leaving, due to the waring pops out.

The disconnect happen 3-4 times on 10/18 pvp and end up giving me a warning from the leaverbuster today. But I work hard in the first 30 min before that disconnect and try to wait for that misleading "Attempting to reconnect" to do something. But it is not working at all.

Later I learn from other players that I have to ignore that warning, exit the game by hitting esc ->exit game -> leave and go back to lolclient to Ok and reconnect. There is a misleading on EXIT and reconnect after the new update causing all my problems here. ( before 4.18 it's not that confusing how to reconnect to the game)

Please at least have some guide on new players like me about alternative way to reconnect. So far it's so misleading after the update.

Thank you.