@fatih1 If you get the Tether app you can manage the router with this app, but nothing more, i.e. you won't get an SSH console access.

@fatih1 TP-Link home routers don't offer an SSH access. The TCP port 22 is open exclusively for the Tether app management - details.

@KYL88 You can try experimenting with the transmitting power of the AX72 to see if that helps in your case:

@Falcon_II You have to switch your C6 to AP mode back so you can access your printer and hard drive - details (Case 1). You have to disable C6 DHCP server and leave the Virgin router to be your main...

@RAFFAR You can do that easily by using this guide.

@PeterKont87 To troubleshoot this issue you have to open the router web managment page in a web browser and check the WAN / Etehrneport status: Here's how to find your router IP address.