I had this same issue. First, go to ping optimizer, click advanced, and make sure congestion control mode is set to Auto. What fixed my issue was going into settings, selecting WiFi, Advanced, and changing both WiFi channels (2.4/5 ghz) to manual and setting width to highest number ex. 2.4 = 40 mhz and 5 = 160 mhz. Choose a channel for each band. I would advise you use a third party app to find an unused channel for each band in your area. Best to not use a channel your neighbor is using. Reboot router and see if this works for you. FRASER, when the WiFi option is set to Auto, it sometimes seems to want to default to 20 mhz for each band which significantly reduces speed. Have not had the problem since I switched to manual mode and selected highest frequency for both bands. Just an FYI.
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