Correct. 1 confirmation is usually enough for most day to day things. 2/3 confirmations is forever IMO.

I'm gonna give you the technical answer first, which is read the whitepaper: Every block mined makes a reorg 2x less likely doubling with every block (source: https://bitcoin.org/bitcoin.pdf)

"Section 5 under "Network": "Nodes always consider the longest chain to be the correct one and will keep working on extending it. If two nodes broadcast different versions of the next block simultaneously, some nodes may receive one or the other first. In that case, they work on the first one they received, but save the other branch in case it becomes longer. The tie will be broken when the next proof of-work is found and one branch becomes longer; the nodes that were working on the other branch will then switch to the longer one."

Realistically, this 1 block reorg still happens on Bitcoin sometimes (example: https://www.coindesk.com/tech/2021/01/21/the-bitcoin-double-spend-that-never-happened/) however, I don't know of any cases in recent times when we've had deeper than a 1 block reorg. If you happen upon a 2 block reorg, we'll all be very interested to read about it.