Here's the build log:

Running build in Washington, D.C., USA (East) – iad1
Cloning github.com/myusername/drupal-nextjs-marketing-site (Branch: main, Commit: 385d2da)
Previous build cache not available
Cloning completed: 595.12ms
Running "vercel build"
Vercel CLI 35.2.3
Installing dependencies...
npm warn deprecated inflight@1.0.6: This module is not supported, and leaks memory. Do not use it. Check out lru-cache if you want a good and tested way to coalesce async requests by a key value, which is much more comprehensive and powerful.
npm warn deprecated rimraf@3.0.2: Rimraf versions prior to v4 are no longer supported
npm warn deprecated @humanwhocodes/object-schema@2.0.3: Use @eslint/object-schema instead
npm warn deprecated @humanwhocodes/config-array@0.11.14: Use @eslint/config-array instead
npm warn deprecated glob@7.2.3: Glob versions prior to v9 are no longer supported
added 434 packages in 38s
151 packages are looking for funding
run npm fund for details
Detected Next.js version: 14.2.5
Detected package-lock.json generated by npm 7+
Running "npm run build"

example-marketing@1.5.0 build
next build