Just a couple quick things I want to add to your comment (which is in no way wrong, as far as I know!) that you missed or I wanted to add to:
The AFK system runs entirely differently, with increasing levels of Low Priority Queue (LPQ - A mandatory delay between queuing and the queue actually starting, which is reset upon interrupt) as follows:
- Warning
- 5min LPQ
- 10min LPQ
- 20min LPQ
I have no actual idea what's past 20 minute LPQ, because I've just never heard of anyone going past it. I assume it either continues escalating indefinitely until you're effectively permabanned (Any time after an hour or so would just be so absurdly long you could very well never manage to get through LPQ) or until you're actually permabanned.
I also believe Riot will issue indefinite bans for chargebacks, which can certainly be permanent.
Also, you can technically get a 25 game chat restrict without actually ever seeing a 10 game chat restrict. You'd need to get a 14 day ban first, then decay two punishment tiers. But, generally speaking, nobody's going to see a 25 game restrict without first having a 10 game restrict.