Nighthawk AC1900/R7000 Slow WiFi

[6446bmw]

Using a Netgear CM1000 modem with wired speed tests of 300Mbps.  WiFi Speed Test results 22Mbps.  Wired speed test results from the AC1900 router is 22Mbps

ISP is Spectrum.

Ookla and Fast.com used for speed tests.

AC1900 Firmware version: V1.0.7.10_1.2.3

Network is private.  Cat5 cable to router has been replaced.

Have powered off devices then powered on modem, waited, powered on router.

My AC1900 is probably at least 6 years old.

Any assistance is appreciated.

[FURRYe38]

Has a power off for 1 minute then back ON with the ISP modem and router been performed since last update?
Be sure to restart your network in this sequence:
Turn off and unplug modem.
Turn off router and computers.
Plug in and turn on modem. Wait 2 minutes for it to connect.
Turn on the router and wait 2 minutes for it to connect.
Turn on computers and rest of network.

Has a factory reset and setup from scratch been performed? A complete pull of the power adapters for a period of time after the factory reset then walk thru the setup wizard and setup from scratch with a wired PC and web browser. https://kb.netgear.com/22697/How-do-I-install-my-NETGEAR-router-using-the-router-web-interface
Recommend setting the default DHCP IP address pool range to the following after applying and a factory reset: 192.168.#.100 to 192.168.#.200.
https://kb.netgear.com/24089/How-do-I-specify-the-pool-of-IP-addresses-assigned-by-my-Nighthawk-rout...
https://kb.netgear.com/25722/How-do-I-reserve-an-IP-address-on-my-NETGEAR-router
I would power OFF the ISP modem for 1 minute. Factory reset the router and power it off. Power ON the ISP modem and let it sync. Then power ON the router and walk thru the setup wizard again using a wired PC and a web browser.
Press the back reset button for 15 seconds then release. 
https://kb.netgear.com/9665/How-do-I-perform-a-factory-reset-on-my-NETGEAR-router
https://kb.netgear.com/24233/How-do-I-erase-the-configuration-settings-on-my-Nighthawk-router

Be sure your using a good quality LAN cable between the modem and router. CAT6 is recommended.

[plemans]

2 things. 

1. you're on really old firmware for the R7000. Try installing the V1.0.11.136 version manually and do a factory reset as there was quite a few changes. Leave QoS, access control, traffic monitoring, and parental controls all disabled at those speeds. 

2. Make sure you're testing the 5ghz. The 22mbps can be normal for 2.4ghz (because it suffers from interference and is a slow network). But 5ghz can hit faster speeds.