Was rather shocked to find BT hubs don't allow you to change DNS servers anymore and force you to use their own ones, so I can't properly setup adguard.
What routers are people using now that are reliable and will let me control my own network configuration
If you don't want to go the route with building your own hardware there is also mikrotik with which I'm pretty happy. Something like the hex s is pretty cheap and has a sfp port if you have fiber.
Excellent choice. I'm running a physical Routerboard and a virtual RouterOS inside my hypervisor for redundancy.
The license for virtual RouterOS is dirt cheap and has more features than you could ever dream of with any of the the big network device manufacturers.
The physical devices are very well designed for their relatively modest price and likewise fully featured. Perfect for any home lab or to play around with IEEE conform protocols.