Smart TV keeps losing network connection

[#1]

I've recently installed the new EE router, but since then my samsung smart tv has kept losing its network connection.  I can get it reconnected but it doesnt last more than a few hours.

I phoned EE up and they sent a new router out, the same thing happens.

They said if it didn't work then they'll send me an older router, but i'm worried i they do i won't get the faster speed.

Could it be slower with an older router?

[#2]

You just discovered the TV was living on the edge of the coverage with the previous router.

I'd keep the new & speedy EE Router and invest a home network suitable for the size and structure of your building.

[#3]

what would i need to buy to make the new router work?

Is there any reason why things like alexa that are even further away work fine?