For third party cooling for a 280X, you basically have the choice of:
Artic cooling.
https://www.arctic.ac/eu_en/products/cooling/vga.html.
Do both liquid cooling and air cooling. Neither options are very cheap.
NZXT G12 adapter
https://www.nzxt.com/products/kraken-g12-black + one of the Kraken AIO. Again, not a cheap option.
EKWB stuff is for proper custom loops, so that's out. Corsair do conversion kits for their AIO coolers, but you need the blower fan from a reference design card and don't think Corsair make a kit for the 280X anyway, so they are out as well.
All options are generally based on reference pcb design, so if Gigabyte has done any weird shit with a custom pcb, you might be out of luck.
Other than changing, you could try a custom fan curve. Reviews say the 280x windforce has an aggressive fan curve, you can notch it down a bit without much of a hit to temps. Could also replace the fans, like most customs cards the windforce has a rather nice heatsink under the shroud, 2 decent 120mm fans zipped tied to the heatsink would probably do a better job and be quieter. Just need to buy/make the relevent adapter to hook the fans into the cards pcb. Doesn't look pretty, but it's actually a pretty common solution and tends to work well/better than stock. I've done it myself when the fan on my old 5850 died.
