Yarn 4 requires Node.js ≥ 18.12.0. Node.js 12 (EOL April 2022) does not come close to satisfying this. Yarn 4 refuses to run. Node.js 12 also predates many modern Node.js APIs. Upgrade to Node.js 20+ immediately.
Minimum version required: Node.js 18.12.0
Workarounds & Fixes
Upgrade Node.js to 20 or 22 before migrating to Yarn 4