Yes, generally the more Zigbee Router devices you add the better your Zigbee network mesh will work, just be sure that they always have power to remain permanently connected (as a mistake many make is connecting a Zigbee lightbulb without removing the dumb switch which someone then turn off and on). Highly recommend you read and follow this → Zigbee networks: how to guide for avoiding interference and optimize for getting better range + coverage
Tip is to add a few “known good” dedicated Zigbee Router devices and personally I can recommend buying a few IKEA TRÅDFRI Signal Repeater and Aeotec Range Extender Zi.
For the best you can get recommend to make yourself some semi-DIY Zigbee Router devices by buying and flashing the correct Zigbee Router firmware to good Zigbee Coordinator USB dongles and then using them as stand-alone Zigbee Signal Repeater devices in USB-chargers for power, like, for example, either the Sonoff ZBDongle-E (EFR32MG21 based) or the Sonoff ZBDongle-P (CC2652P) work great as dedicated stand-alone Zigbee Signal Repeaters when using Zigbee Router firmware.
Again see this for even better suggestions and more recommendations → Guide for Zigbee interference avoidance and network range/coverage optimization