I got an offer to make this ring, but I have absolutely no idea of how I should do it (I'm using Zbrush). I'm looking forward to hearing your opinion and any tip, thank you.
In theory, you can model such a ring in your program. Try to sketch out a "outline" for the ring, and then work out the detail.
Why can't you make it in your program? Are you afraid of these small details on the ring?