Smart contracts are not scalable in linear and synchronous blockchains such as Bitcoin or Ethereum because in those blockchains every single node is needed to arrive at consensus which would render the network impractical for decentralized application that require high throughput and fast finality while being able to scale globally.
https://docs.openzeppelin.com/contracts/4.x/wizard
https://ethereum.org/en/developers/docs/evm/
https://takenobu-hs.github.io/downloads/ethereum_evm_illustrated.pdf