When I lived in Dubai I used to order parts for my KLX450R from
www.motosport.com in the USA.
https://www.motosport.com
I used to buy genuine Kawasaki parts, aftermarket parts, helmets, boots, gloves, etc. I always had great service from them and the prices seemed reasonable. I don't think they can supply genuine GasGas parts but pretty sure they stock aftermarket parts.
Or what about eBay? Here in Europe there's some reputable eBay shops selling parts.