The deepest re-orgs were 53 blocks in 2010 and 24 blocks in 2013:
https://bitcoin.stackexchange.com/questions/92974/what-is-the-length-of-largest-known-reorganization-in-bitcoinI'm not aware of any other major re-orgs happening since then, but back in 2017 during the fork wars, most exchanges highly increased confirmation requirements for the minority forks like Bitcoin Cash. IIRC it was in the order of 24, maybe even as high as 100 confirmations on some exchanges. This was due to high hashrate fluctuations and a subsequent lack of reliability in transaction finality.
As the average difficulty goes up, pools tend to run mining software that have a predictable reorg policy, in order to minimize the probability that their own blocks get invalidated. That is why we don't see large reorgs these past few years.