WiFi help

Hi I’m bit clueless with WiFi and broadband, I have my landline from sky which come in upstate bedroom. My sky router is plugged directly into master socket.
I have tried a few different netgear WiFi extender products get WiFi into downstairs room where our living room is where we watch tv.
We can’t get a good enough connection to watch tv, film as it will stream and then loose connection or buffering with poor picture.
And solution help much appreciated

Thanks Barry