Almost all of you say is incorrect...
Reports do set back your reform progress if verified - the system keeps track of everything. Punishments set back your reform progress more (as they actually move you in the other direction). While reports don't mean you'll never reform, if you're constantly reported and the reports are verified, just not at a frequent enough rate to get punished again, the system will slow down your reform progress.
Further, the automatic ban system has never been one to look for key words. It looks for many things based on settings by Riot of what to look for - many times it looks at phrases, words, words in combination with other words, amount of text in a short period of time, etc. There has never been an "auto" ban system for normal toxicity (there has for hate speech/inting), only report-triggered ban system. Your time-frames are accurate but misleading. It takes 1-3 verified report-games to cause a punishment. This can happen over the course of 3 hours, or over the course of 7 days. It depends on how often you're playing, your patterns, if it's a rare occurrence, etc.
If your timeframes are related to key/chest drops happening that quickly after a punishment, the system has not actually changed all that much. It has always been a system based on many factors to determine when drops start happening again ever since loot was introduced.