Yeah Smart Contracts and Lightning Network will be a game changer to Bitcoin and this can destroy Ethereum
except Ethereum 2.0 will be POS while bitcoin is POW.
It depends on what you have in mind when you say "smart contracts".
The wikipedia definition says "A smart contract is a computer program or a transaction protocol which is intended to automatically execute, control or document legally relevant events and actions according to the terms of a contract or an agreement."
Smart contracts have always been available in bitcoin. Genesis block reward went to a smart contract or whenever you someone bitcoin you are using a smart contract in its simplest form. You can also use more complex contracts for escrows, time lock contracts, fund raising, lottery, atomic swaps (cross chain), multi sig,... all of it designed to make sense for a "payment network".
Something like Ethereum on the other hand is mainly designed to let you create "tokens" out of thin air and then use those tokens for whatever you want. This is not something that can ever happen in Bitcoin because there is little to no utility for it.
As for PoS, the centralization in Ethereum is sacrificing the security of PoW so that they can earn money by only being the owners of the 72 million premined ETH. They also know that the uselessness of their shitcoin plus its unlimited supply and the dumping that they experienced the past 4 years will continue making PoW mining harder and harder which means in near future as ETH price dumps hard the hashrate drops with it and ETH becomes open to 51% attacks so they are trying to change the algorithm so that they can fully control the network by owning all the "stakes".