$ ng version
Angular CLI: 15.2.7
Node: 18.16.0
Package Manager: npm 9.6.4
$ ng serve --environment=prod
Error: Unknown argument: environment
$ ng version
Angular CLI: 15.2.7
Node: 18.16.0
Package Manager: npm 9.6.4
$ ng serve --environment=prod
Error: Unknown argument: environment
Found a fix, written an answer on github here: