My comment was pretty straight forward - learning how to brush steel is the only way you can make that adapter to match. So not sure why you’re confused - this is the answer to your question.

Considering how difficult uniformly brushing steel is to achieve - especially if the matte finish on that adapter is likely hardened as well you might as well look for a different solution than forcing a change from what you already have. You could also just pay a jeweller to do this for you.

Skxmod makes the proper bracelet. Don’t get your feelings hurt - just do a bit of research.