Our Fritz!Box is a model 7530, which supports Wi-Fi 5 (i.e. 802.11-ac).
It can act as a Mesh hub, and can be used with Fritz!Repeaters. It's also possible to use Fritz!Box 7530's as repeaters. Used ones are available cheaply from eBay, and have the advantage of having UK mains plugs - the Fritz!Repeaters only seem to be available with European mains plugs.
Extend your home network with Mesh
Mesh Wi-Fi setup – easy with FRITZ!
Mesh with FRITZ! (in user manual)
Setting up the FRITZ!Box as a Mesh Repeater
Finding the ideal location for the Mesh Repeater
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