Wheel well lip trims are anodized and without removing the anodizing, polishing options are limited. Replating isnt the right process either. Also as you know tiny rock and debris pits also pepper the rearward parts and sanding them out goes through the anodizing just in those areas. There are anodized aluminum specialty polishes: Simichrome and autosol are the best. But they are limited in what they can bring back esp. if pitted.
Its not hard to de-anodize using common chemicals (lye-based oven cleaners primarily.) The lip mouldings are weird and unwieldy shapes so you would have to work on a plastic sheet or tarp and brush it on, let it work, and rinse well. This is messy and caustic skin burn stuff - requires lab gloves and a lot of ventilation.
When the process is over you have gray ugly aluminum that no longer has the layer of hard oxide anodizing. Now you can sand, scotchbrite and start an aluminum polishing sequence of buffs and polishes.
Or you can avoid all this and just sand prime and paint (try Eastwood bright aluminum) or Plastidip ..