+1 for Farsports. I have a custom road wheelset from them that cost me about 780 and it's been solid. There are many ways to order from Farsports, I suggest contacting Mae on Whatsapp/email/Alibaba for the best prices and options.
I also just ordered a 6 spoke gravel wheelset from Leon (Yuanan). Great prices. I can't vouch for quality just yet as I'm still waiting for them, but it's essentially the same wheelset as the Elite Drive Gravel 6 and the reviews on those are pretty good.
Other than what has already been mentioned, I think your wheelset is already pretty solid and you'll be hard pressed to find a real "upgrade" under 800. I think if you open up your budget to ~1000, there will be many more options that will feel like a real upgrade (Magene, Light Bicycle, 9velo, nice Farsports options, etc).