This seems to be largely a new player problem (sort-of-thankfully). They've never really properly addressed it and never will. As long as the game remains free, it will have bots. I always imagine some sweaty guy five-boxing League to level five accounts and just sort of half-assing it on them all and ignoring chat.
Anyway, you basically report and move on. A lot of things make League hard for new players, including new players, players, and League of Legends. Unfortunately, bots are one of those many things but the one they have the least agency over arguably.
I mean, I'm not sure how to continue on that other than to tell you to keep at it. I've got more games of ARAM than I care to calculate (near the 4k mark) and I dunno if I see bots; I keep all chat off (cuz all chat warriors are just fucking everywhere, damn) but I'd wager everyone I've faced in the past two years is a player.
More common than bots (if I'm to be believed) are AFKers/leavers/griefers.
So yeah... stick with it, and eventually it gets bett...
...well, different. And that's something. I mean, it's not something. But it's more than nothing. Even if it's less than something.