The answer is Yes plenty of videos how to do this on YouTube. To use a 2nd Hub ...I done this myself to give split 2.4 and 5ghz signal ..only the best option is to get a BT complete WiFi Disc If you got a BT smart hub 2 and run an ethernet cable from Hub to WiFi disc you don't have to use ethernet cable only this will give the best WiFi signal from Disc..depending on your BT package Phone BT sales may give you one at no extra cost
There is a long an excellent thread on the AV Forums about repurposing a router as a switch and access point. I’ve been doing this for years and it’s a great way to get the most out of kit. In fact my old repurposed Plusnet router performs much better than my BT Smarthub in terms of Wi-Fi. I would also recommend a utp terminating kit/cutter and checker. Not a lot of money but very useful.