My sister and her husband built a home recently and they've remained with their previous ISP for internet, which includes still paying a monthly sub for the ISP-supplied router (a very old and yellowed Huawei HG659). They've installed this in the roof space above the garage, which is also where all Ethernet cables from around the house terminate (no switch IIRC). For WiFi they primarily rely on the Huawei (which is at one end of the house) but have an old router set up as an additional AP (not working properly).
Can I please have some recommendations for suitable products to both replace the router and provide decent WiFi coverage throughout the house?
Ease of set up and operation is an important factor as they're not really IT savvy - I had thought something like the TP-Link Deco unit and one or two mesh extender/s connected via Ethernet (such as that supplied by Vodafone) would be ideal as that can also manage router duties and they're simple to set up and use. But it looks like the Decos don't support VLAN tagging (which I understand is needed for their ISP, Voyager) - are there other similar products that will work with Voyager?
Also, I just wanted to check whether there's any possible way to relocate their router to, say, behind the TV in the lounge: I'm thinking that to do this they'll need to have two Ethernet ports in that room, one to connect the ONT (in the roof space) to the router (lounge), then a second to connect the router back to a passive switch in the roof space to allow connection to the Ethernet ports elsewhere in the house - is that on the right track? I'm not 100% sure but I'm doubtful they'll have more than one port per room, as it looked pretty scant re # of cables in the roof - if so, are they stuck with leaving the router (and switch, if needed) in the roof space?
Thanks for any advice.