Hi Gben, welcome to Autopia :wavey
I've kinds struggled with this for a long time. The first instinct for me was to use either a tire foam or clear silicone based dressing. The problem with those is that they attract dust and they wash off even in very light rain or if exposed to puddles. Then, I figured to try AA, 303, that whole family of PDMS dressings. They attract dust a lot less but again,expose them to water and they're gone.
Meguiar's used to make an acrylic based dressing called Engine Kote, and that was ( I still have) the best solution for me. I've replicated the results on some ( but less than more) wheel wells with Mop & Glo floor shine. Others have used Future, maybe with even better results. I think the products are extremely similar with EK not having cleaning ingredients the floor shine products do.
Although EK is gone now, Sonus has a very similar product: Trim and Motor Kote. It's a shame it doesn't come in gallon sizes.
The dust with the EK applications didn't seem as big of an issue and it held up to mild to moderate exposure to bad weather. The problem with that is you can't spray it on and walk away. It needs to be spread to look its best. Droplets could dry and look bad and be hard to remove if you don't So, what I do it spread it evenly with a long handled sponge intended for bathrooms. Walgreen's is the only source I know of for them.
My next plan for a closer to permanent shine to the wheel wells is applying some clear Trimonex trim and cladding product to the wheel wells. as I understand it, it provides a nice, long lasting barriers from the elements. It would be great to just have to simply wash the wells and have the shine restored without constant re dressing.
Of course, the old clear spray paint may do the trick also. I'm unsure exactly what type of paint might be used. If anyone experiments, please report.