One other thing that could possibly help improve your connection is to disable Network Manager’s WiFi power saving features with the following command:
echo -e "[connection]\nwifi.powersave = 0" | sudo tee /etc/NetworkManager/conf.d/default-wifi-powersave-on.conf
Then, reboot both your router and your computer.
A setting of “0” in the /etc/NetworkManager/conf.d/default-wifi-powersave-on.conf file will totally disable power saving features in the WiFi adapter.
A setting of “2” or “1” will be less aggressive, but still leave power saving enabled.
If you find that the /etc/NetworkManager/conf.d/default-wifi-powersave-on.conf file is of no benefit, then it would be best to delete it after testing.