A little late for replies but as I had the same problem I thought I would pitch in to help any others in the same boat.
Hopefully helping someone avoid the many months of Google-izing to figure all of this out!
As others have said ISP routers tend to be rubbish. They aren't going to hand out top of the line routers for free.
Their mesh options are also very limited and tend to be dual band only, reducing the overall bandwidth available.
An example of dual band is the EE wifi 6 router and wifi plus offering, it isn't terrible but the speed drops off significantly at distance. Dual band utilises, either the 2.4 Ghz channel or the 5 Ghz channel to stream data between mesh nodes. This reduces the bandwidth available for client activity.
Mesh is the way to go if you want nearly the same speed in a far away room as the main router.
However, ideally you want tri-band, one 2.4 GHZ channel and two 5 GHZ channels, one solely for backhaul connectivity to keep clients and data flows separate, having the mesh nodes wired is better, but not totally necessary. This is where things get complex and it took me a while to realise it.
Going beyond wifi 6, to 6E or 7 at the moment is severe overkill and will potentially make you worse off. Not only are these options much more expensive but they are a bit of a con in my opinion.
Top of the line wifi 6 mesh systems are typically tri-band, with the obvious benefits I have mentioned above. Wifi 6E mesh systems are also advertised as tri-band but this is not the same meaning as it is for wifi 6, it means you have three bands, 2.4 GHZ, 5 GHZ and 6 GHZ, there is no dedicated backhaul channel on these so data must travel on the same channel as client activity if you use 5 GHZ or 6GHZ. As you can see this is almost false advertising. I was nearly going to hop from my mesh system to a 6E system, until I realised the ruse. My mesh system is originally a two node Asus XT8, wifi 6, true triband offering. I added an additional node I picked up from CEX. I am a large distance from the main router in the living room at the front of the house, to the office at the back of my house. I use wireless backhaul from the main router to the middle node and wired from that node to my third node in the office. I am on the 900 full works package and I get over 850 Mbps in the office, sometimes the full 900. My entire house, including my garden gets full strength wifi on the 5 GHZ channel. I get 300 Mbps at the bottom of the garden.
So you can see jumping to a more expensive option may actually be detrimental. They are addressing this with brand new offerings, Asus do a quad band gaming router now, with dedicated backhaul for mesh. This is very new however and very expensive.
Which brings me to my next point. Mesh doesn't have to be very expensive. You can mix and match routers and extenders to make a mesh system of your own. Asus offer AiMESH, which is fairly standard across their range, adding nodes is child's play with a mobile app. You can use cheaper kit found on Ebay etc. to mix and match to your needs. TP-Link also offer a good option, I believe it's called One Mesh. Just make sure that if you are getting kit, that it's triband, doesn't have to be of course and dual band is still performant, just not as speedy as it could be.
This is my experience of course, others may argue 🙂 All I know is I work from home and so does my wife sometimes. Neither of us experience any issues whatsoever and we are both on Teams calls at the same time etc. with not so much as a blip.
The kids also stream in 4K in their rooms, and while they are on their phones, no complaints at all!
A fire breathing monster of a router can deliver results, but cannot compete with mesh at a distance. The thing being that a mesh system may in fact be cheaper than that router.
Again sorry for the late reply and I hope it helps!
