If the Plusnet Hub Fibre router is the "Plusnet Hub One" model then it is dual band and supports both 2.4GHz and 5GHz bands. The 5GHz is the most reliable band (see click here but, if the Gigabyte Wi-Fi card only supports 2.4GHz then that is less reliable. If it only supports the 2.4GHz band are you able to swap it for a Wi-Fi card that supports 5GHZ band? Also router location is important. See click here .
Google Home Hub review