Cat 8 is useless to you. So is cat 7. Both are shielded cables and require compliant network ports, with shielding/grounding. They also both use different connectors to standard cat5e/6/6a Ethernet. Your gaming console and SuperHub don't have this specification. Extremely likely neither does your switch, or any of your home network devices (PCs, laptops, consoles etc).
Higher numbers for Ethernet cable doesn't mean it's automatically better, though dodgy Chinese eBay sellers will happily trade on people's ignorance with terrible quality 'Cat8' and 'Cat7' CCA cables with little or no to-spec shielding and terrible quality (or non-existent) twisted pairs. Ironically, anyone who actually knows their onions at Virgin is far more likely to blame your cabling when they realise you think you have "Cat 8"...and like I said, unless your device ports, switches and router are also Cat8 compliant, you don't.
Cat 6/A for example is actually a newer standard despite the lower number, and doesn't require shielding to achieve 10Gbps over 100M. Quality UTP copper cat 5e is ample for gigabit at 100M and 10Gbps over around 50M. Exceeding cat5e (eg cat6(a)) has absolutely no impact on your gaming whatsoever. As for who is gaming on cat 5-7? That'd be pretty much everybody...
While I realise that issues or faults are frustrating, you're looking at the wrong metric. Having even 180Mbps downstream is laughably overkill for gaming, or even for watching four 4K HD streams whilst you game. You can game at 10Mbps without issue. If I were you, I'd be more concerned with the latency and jitter inherent in DOCSIS versus DSL or optic technologies. Either way, I hope you get sorted soon. If it's down to local over-utilisation (i.e. over subscription) I wouldn't hold your breath...
