Before this, cds init --nodejs and cds add --nodejs scaffolded CommonJS projects by default. The default flipped to ESM; a CommonJS project now needs the explicit cds init --add cjs. capire's changelog tags this at cds-dk@10.0.1, but 10.0.0 and 10.0.1 were never published to npm — 10.0.3 is the first version on that line that resolves.
Any generated-project walkthrough that shows require() and module.exports coming out of a bare cds init — on cds-dk 10.0.3 and later, a fresh Node.js project is ESM unless --add cjs was passed.