Then simply make the two transactions? But not just one of them. It's hard for a "smart contract" to securely do a transaction on a blockchain not its own. A

Then simply make the two transactions? But not just one of them. It's hard for a "smart contract" to securely do a transaction on a blockchain not its own. A trustless system needs an atomic commit across two different blockchains, which is hard. See [1]. [1] https://www.cnbc.com/2022/08/10/hackers-have-stolen-1point4-billion-this-year-using-crypto-bridges.html https://www.cnbc.com/2022/08/10/hackers-have-stolen-1point4-...