Aliexpress
Here are coupons that you can use.
Latest coupon and price update (UTC):
Banggood
Banggood warehouse is located in China.
Link: Banggood product page
Coupon (199.99 USD): BG30aa20
Coupon (347.79 USD): BG589b2e
(CouponsFromChina.com tip: paste coupon code in your cart and click Apply after clicking “Proceed to checkout”. Click to copy code and open shop)
Exclusive Allowance Coupons: https://bit.ly/3xWgD9k
Old coupons (from the oldest to the newest): BGWSCYT1, BGMIAX117001, BGc550c0, BGde2f67, BGc6acaa, BGc209d1, BGce7db1, BG1bce5f
(probably won’t work, but you can try them out)
Price history and price alert
Here is price history (for all/most countries) for Xiaomi HomeWiFi WiFi6 Router 2-Pack Tri-band Mesh AX11700.
Price records source(s): Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).