Description:
After upgrading from webpack-dev-server v4 to v5, I am experiencing significantly increased server startup time and slower test execution. No other major configuration changes were made

Details:
The dev server takes 20–30 seconds longer to become responsive (many repeated ECONNREFUSED errors before it starts serving). Each test spec now takes 2x or more time to complete compared to v4. This happens both locally and in CI.

Versions:
webpack-dev-server: v5.2.1
webpack-cli: v6.0.1
Node: v22.11.0
OS: Windows and Linux