What happens if the blockchains of 2 different peers are inconsistent?

Question

bitcoin

Let's say one of the peers connects to another, compares its blockchain with its blockchain. If the connecting peer's blockchain is shorter than the one it has connected to, the connected peer takes over the neighbor's blockchain. But what happens when the lengths of the blockchains are the same, but the last block of one blockchain is completely different from the last block of another?

Answer 1

an alternative branch appears. if someone mines on it, an alternative currency appears, such as Bitcoin Cash or "If the connected peer's blockchain is shorter than the blockchain of the one to which he connected, the connected peer takes over the neighbor's blockchain" .
You can create your own alternative chain, but no one will need it.
therefore, when paying, confirmation of 3-5 mined blocks is considered reliable.