Do you know if you're connecting to Wi-Fi on the 2.4 GHz or 5 GHz band?
If it's 2.4 GHz, unless there is a specific need for it, I'd disable it on your router. It's congested, slow and unreliable in RF-congested environments.
If you are using 5 GHz, download something like the Ubiquiti WiFiman application on your phone to check for nearby networks and devices which might be interfering with yours. If your wireless router/access point isn't doing a good job of finding a free/less congested channel, you might need to force it over to something more suitable yourself.