The EMI shield on Cat8 cables could even make the signal worse if the equipment and the port is not properly grounded, and that is not the case for most home networking environments. I would still recommend buying Cat6a cables.
And secondly Cat 8 is very thick making it hard to install. Cat 8 is for 40 GBs most homes do not even have 2.5 GB let alone 10 Gb. Thirdly Cat 8 can only go a distance of 98 feet.