Can mainlanders go to work in Hong Kong?

Obviously you can. There are several ways.

As a senior talent, you are introduced to a local enterprise in Hong Kong, which will solve the problem of Hong Kong hukou for you.

If your current company is a joint venture, you will have the opportunity to be sent to work and study in Hong Kong as a designated person, and you will generally be issued a temporary residence permit there. The advantage of a temporary residence permit is that you and your spouse can give birth in a local public hospital, and your child can choose to register for a Hong Kong hukou. If you go back to the mainland in this way, your child's account doesn't need to be changed, and you can receive British education in Hong Kong at any time!

As an ordinary wage earner, you should pay attention to your Hong Kong and Macao Pass. You shouldn't get a pass to travel or visit relatives to work in Hong Kong. Otherwise, the local immigration office will send you back to the mainland.