You can check the Wi-Fi strength in settings.
Have you the opportunity to test it when hardwired to your router with an Ethernet cable?
You can try resetting the device.
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Wifi strength is fair to high;
unable to hardwire, wifi only;
reset didn't work.
We have used pik tv in the wifi only configuration for the last three years with no significant problems. It is only in the last few days that it has been freezing/loading/buffering.
One thing that has worked for others in the past is to turn off the Wi-Fi in the Android TV settings (Settings --> Network & Internet) first and then reboot (Settings --> Device Preferences --> Reboot).