Should be noted that most dedicated Zigbee Router products are usually better a Zigbee routers than a non-dedicated Zigbee Router product.
For example, “IKEA Trådfri Wireless Control Outlet” (a smart power-plug) is known not to be a very good Zigbee Router, while the “IKEA Trådfri Signal Repeater” is known to be a very good Zigbee Router.
Personally, I recommend that Zigbee beginners add a few dedicated Zigbee Router products as they are not expensive and being dedicated there is less chance you/someone will move or power them off.
And you should know that you can very easily convert many Zigbee Coordinator adapters into a simple but great DIY Zigbee Rouuter by flashing them with the proper Zigbee Router firmware and then power them via a standard USB changer, …those with external antenna normally work great for this purpose!
Again, more on that here → Guide for Zigbee interference avoidance and network range/coverage optimization