How do you keep yourself safe when using custom domains for email addresses?

As seen in the recent thread in this sub, the whois registry information (when hidden) can be revealed against money and it made me worried about my personal information possibly getting leaked.

So I'm asking what tricks are you using to hide your personal information when getting domain and how much information are you giving when doing so? Some people have said to use only pen names when purchasing and others are just using their own information with PO box …

addresses asking custom domains domains email hidden hide information leaked money personal personal information privacy registry safe whois