5000 sq ft is not an issue. We’ve created setups with a single hub covering 12,000 sq ft of house (yes house, not open space). It requires a good design/layout.
The key thing would be to have a good number of repeaters to give good coverage.
A note about z-wave repeaters, they have a 4 hop limitation so it would be great it keep the hub centrally located (if you have a v3 wifi hub then that should be easy). See this post for more details on how to design and check your z-wave network.
Similarly for ZigBee device you should have zigbee repeaters (mains powered devices). They don’t quite the same limitation as Z-Wave but keep in mind the longer the repeating distance the more the chances of errors and slower the response times. JD has some greats links for ZigBee design.