I have 2 deco P7 units. The primary deco is connected to a tplink archer router. At first connection, i can get ookla speedtest 300-400mbps from my mobile when connected to primary deco. But after some time, i will only get 90mbps on speedtest. I will need to power down modem, router and deco which usually after restart, i get 300-400 mbps. But again, after some time, it drops to 90mbps on primary deco. How can i get my deco to maintain consistent 300-400mbps?

Note: i previously connect primary deco to modem direct and its same problem as above. No difference

My settings:

- access point operation mode

- fast roaming enable

- beamforming disabled

- wifi setting on 5ghz only