Router question

[chili]

Fist off i am a complete novice.
My isp is sky fibre i have never had any issues with their service, only issues with their crappy routers, so armed with wireshark i got got my sky tied routers password etc for that "just in case moment"
i then purchased myself a tp-link router an ac1200 vr400 thing and everything improved. when i set it up i put in the sky login details i got from wireshark.

Q1 do i still need to enter these details even though i no longer have sky hardware, or can i leave blank? (they are in there at the moment)

Now the reason i am asking this is my son has lost his details for his router and has poor wifi in his house because the router is stuck in a cupboard, i have given him a couple of tp link plugin extenders to use which seem to have made some difference, but i did
suggest he buy another router and a mesh device or 2 for other spots in his house.

Q2 will he need his original routers information or will it be just plug new router in and off he goes?

Sorry if i have not explained this very well, thanks

 

[Caged]

Sky don't use the login details if you're on their 'new' network (95%+ of their FTTC services, 100% of FTTP). You just need a router that can request an IPv6 prefix, once it asks for that the DHCPv4 server will start to respond and issue an IP address. This is their way of making sure a router is connected, as clients don't request a prefix.