One option for some people, not everyone, is to just do your project on your own time and equipment and share it online. Don’t tell your boss, but make sure that some random people out there are forking it. Probably the boss never finds out, but even if they do, they won’t do anything.

Obviously this is slightly risky, but for many people it is a reasonable move. All depends on the details.

You are repeating what your employer told you, not the actual law. Of course hiring lawyers would be expensive so it’s best avoided, which is why OP is here.

The first sentence is false. The second sentence is debatable.