This ORB is probably a powder coating and as you have discovered, a powder coatngs require more care in cleaning.

I presume that since you did not install the fittings, you don't know who makes them. But if you do, go the mfgr's website and follow its cleaning instructions.

Otherwise use a mixture of 50% Bar Keeper's Friend (BKF) and 50% diatomaceous earth (DE). You can get these on most general merchandise websites (Amazon, Walmart, etc.) Most DE is "food grade", although why anyone would eat the stuff is beyond me. It looks very unappetizing. You don't need food grade and standard is usually cheaper.

These give you a mild acid and a very fine scrubbing agent that works on most faucets, showers, and porcelain sinks. Be sure to rinse well, however.

Test it on an out-of-the-way surface first.

The finish was scrubbed off using abrasive cleaner. I happen to actually read the information that came with my last bathroom sink faucet. It said to not use abrasive cleaner and to use a soft cloth to clean with. Modern/cheaply made, even higher end, are not the same as they were decades ago. The finish is a coating not very thick.

I actually was thinking about looking for uncoated solid brass but I don't know if that even exists anymore. I have hard water so scrubbing would be my go to but I use a lime away kind of cleaner now.

Uncounted brass needs constant polishing and is a maintenance nightmare. Try PVD brass instead. It never loses its shine.