I always wondered what's a "gaming router". We put "gaming" to every single electronic and the result is...? gaming TV, gaming washing machine, gaming air condition, gaming printer...
What I understand is that the router has a better wifi than some other regular router, specially the ISP one. But in my country, you need to do arrangements if you want to replace the ISP router.
Having done it personally and professionally, I would recommend anytime to use ethernet cable unless the device you're connecting has no ethernet port, such a mobile phone. And even more, better to have a decent fiber media converter then the router you want to use to do the pppoe or whatever your ISP forces you to do. It is kind of pointless to have your ISP router, then your new router, it's 2 hops and that only degrades your internet and response time.
Particularily, I've done both configurations at home for testing purposes and replacing the ISP router completely is the clear winner. In addition, I was using a professional Fortigate firewall in my case, because older models get very cheap and they are very powerful.
So, that would be my recommendation, first check with your ISP and on internet if you can replace their router :)
