Can one Mac user have 2 Apple IDs?

Correct. You would need to create two separate profiles on the Mac and log into the computer using either personal or business; and switch between those.

No. You can use two separate accounts on your Mac, one personal and one for business.

Romath wrote:

I have a personal and a professional Apple ID. Is it possible to have both signed in at the same time, same user for Messages on my Mac?

thanks.

Manage and use your Apple ID

Apple ID - Official Apple Support