Hi
May we know if you are using the wired Ethernet connection as the Internet source of Flint 2?
If yes, as 9b9e… mentioned, please install OpenSpeedTest on the Flint 2 or use iperf3 to bench Wi-Fi performance.
This will help to find whether the issue lies between Flint 2 and the Wi-Fi client, or internally on Flint 2 between Wi-Fi and WAN.