how to add a new color profile

Hi, this might help

https://www.colourmanagement.net/advice/where-are-my-icc-profiles/

I hope this helps
neil barstow, colourmanagement net :: adobe forum volunteer:: co-author: 'getting colour right'
google me "neil barstow colourmanagement" for lots of free articles on colour management

You seem to have issues finding the folder(s) where the profile should go. There are several on the Mac.

Why not use the Finder's "Find" command and ask for "AdobeRGB1998.icc" (copy and paste without the ").

It will locate the Adobe folder named "Recommended" for Photoshop's installed profiles and for the time being, it is fine to place your profile there; at least we know where you put it, Photoshop should show that profile now. 

You will be asked for the Admin password to place the profile in this location.

In Photoshop, it will show up in a higher area of the list but should show up and can be used. I tested this with a CMYK profile called "Blurb" seen below, in this upper location in the list.

If you now see it, fine or we can move it elsewhere. What counts is, that the profile shows up in Convert to Profile (or if you wish Color Settings).

Drag and drop the profile into /Library/ColorSync/Profiles - you will need your admin password. In Photoshop you can go to Edit - convert to profile and choose it. I just did all of these steps on my Mac for screenshots for you. 

One possible location 

/Library/ColorSync/Profiles