The people who blame it on your internet connection are tunnel vision prone people who did not read your post and are usually just toxic people in general who just want to scorn people.
I NEVER have problems on League with connection.
I have Full Fiber Optic internet with 1,000 MBps, yes 1 gig per second. My ping is SOLID 16ms it NEVER changes . I have had this sudden lag issues a couple times and even d/c's . But my internet is working fine, while I was d/c waiting for it to reconnect I ran speed tests on my 2nd monitor, my speed and connection was perfect 900-1000 download AND upload while League is over here saying "Attempting to reconnect" for about 1-2 minutes.
I even kept my Ethernet Connection Throughput graph running so that when the d/c occurs I look at the activity in the graph, and it proves the d/c's have nothing to do with my internet connection.
I have also ,ever since the last update, had a LOT of crashes happen in pre-game lobby where the BugSplat pops up and the client for black for about 30-40 seconds , then comes back to the pre-game lobby as if nothing happened.
I have had a lot of client lag as well. Failing to open the Crafting Section, failing to load the art. (not on login screen , just the client page after logging in) and several other areas the client is responsible of.
League definitely has some problems going on ever since this last update.
Don't let the toxic "Forum Jockey Gangsters" get to you, leave them to their lonely toxic cesspool they call home.
[slayer-jinx-wink]
ps. I am also running on a newer computer with 16 gigs of ram, GTX 1070sc on an i7-7800k. My computer diagnostics proves my PC is running perfect and is perfect condition. The problem is definitely directly associated with League of Legends. (I have no problems on any other games I play)