Nighthawk AXE11000 Tri-Band WiFi 6E Router bandwidth issues

Which WiFi adapter and/or client device are you using with the router?

Also, how far are the client devices from the WiFi router?

The RAXE500 has 3 WiFi radios, The 5GHz and 6GHz radios are 4 stream 160MHz by default, though currently the best 802.11ax WiFi radios for client devices, offers 2 stream 160MHz connectivity.

With my RAXE500 and a laptop using the Intel AX210, under good conditions, especially when in the same room, will offer 1.8Gbps to 2Gbps real world throughput when the PHY rate is at 2400Mbps.

For 802.11ac clients under good conditions, they will offer 500-600Mbps under a 866.7Mbps PHY rate, and for 3 stream radios (highest for client devices), will do around 800-900Mbps at a 1300Mbps PHY.

PS, if you live within radar range of an airport, the 160MHz channel width will not perform as well since the 160MHz channel width uses the DFS frequency range which is shared with radar systems.

PS, the speedtest that the nighthawk app does, is a WAN speed test between the router and the speedtest server, and not from the mobile device.
PS, smartphones will not work to determine the full WiFi performance since many have arbitrary restrictions. For example all of the major brands tend to restrict their smartphones to use 20MHz channel width on the 2.4GHz band even if the AP is allowing for 40MHz on the 2.4GHz band. Speeds are further slowed (often by 40-60% if bluetooth is on and in active use (and Bluetooth device connected to it, since the WiFi and Bluetooth RF frontends on smartphones are often shared, and will end up sharing the airtime, by taking turns transmitting and receiving.