What can I use to protect/shine these metal bumper guards?

[AGAuto]

I have a black front bumper bull bar and a rear bumper guard on my daily driver. Recently I noticed that they are starting to fade color a little bit, and I was wondering if there was any products out there that could protect/shine these guards? I have quite a few products and I'm wondering if I could use any of them, but I am open to any suggestions.

Here are pictures:

[Accumulator]

I'd use an AIO and then top with your LSP of choice. I've even used mild polishes on satin/matte black without overglossing it.

Not sure which AIO you'll like best, I choose between KAIO, ZAIO, and Autoglym SRP. One of those usually does the trick..and then there's VM, but I haven't used that for such stuff in ages.