Would it be better to plug into my openreach fibre modem rather than just plugging into the router, my router is shortly going to be an Asus RT-AC66U. I feel like it is a better idea since the hardware in the modem will only be utilised by me, and the router's hardware will be utilised by the other people in the house.
Pure speed definitely directly to the modem but more secure through the router. I doubt you'll notice much difference either way tbh
I'm a bit confused on what you're trying to achieve here. Are you planning on plugging your PC and the new router directly to the modem? If that modem is like most, then it will only hand out a single IP address - typically to a perimeter router. Directly connecting your PC in situations like this will give your PC the only connection to the outside. I don't know much about openreach fiber modems or PPPoE in general, but a quick search seems to indicate those will only bridge a connection on the first ethernet port when using the stock modem firmware. I could be wrong of course, maybe your ISP is doing something different than what I'm accustomed to. Or maybe that modem is actually a router too, and hands out local addresses instead. Also, it's generally agreed to be safer, even for a single PC, to be networked behind a firewall that runs on a dedicated device. If its a good router, then there will not be any noticeable delay in your traffic - fractions of a millisecond really.
