The build is likely hanging during the deployment phase after your build successfully completes. That can happen if there is a large number of output files or build artifacts not being properly finalized.

First thing I'd recommend is checking for a high volume of output files. If generating thousands of files, consider using ISR instead of SSG or reduce the number of static pages generated at build time.

As a workaround, you could try prebuilt deployments. Vercel CLI will let you deploy from a local build. You can use vercel deploy --prebuilt --archive=tgz to compress the build output and then deploy it.

I hope that helps!