Hello Sbells,
No, the 65Q800T is not compatible with the One Connect Box, all cables are required to be connected directly to the back of the TV. Please check out 8K compatible HDMI cables at Best Buy.
https://www.bestbuy.com/site/searchpage.jsp?st=8K+HDMI&_dyncharset=UTF-8&_dynSessConf=&id=pcat17071&type=page&sc=Global&cp=1&nrp=&sp=&qp=&list=n&af=true&iht=y&usc=All+Categories&ks=960&keys=keys
^Cristian