There is a lot of talking about privacy and privacy protection. There is plenty of commercial value in our personal information. The price for that value is our own time and no one should assume that it is zero.
When we give away our contact information, we offer the time we will spend to read, answer, interact with those who will contact us.
If our contact becomes part of a chat group, then we commit our time to read the posts. Even when we decide to leave the group, we spend time to assess the group and then to remove ourselves.
When people that we don't know can gain access to channels that have our prompt attention such as phone, messaging services, even email, then we offer our time to anyone indiscriminately.
I value my time and the time of others I interact with, for this reason I only offer one first point of contact that is my email. Then, once the person reaching me has offered me information to understand how the value of my time will be used, I may offer other more direct and prompt ways to contact me.
My contact for personal purpose is: firstname.lastname@example.org
My contact for professional purpose is: email@example.com