Hey there and welcome to the rabbit hole!!! 
Z-wave is fairly low frequency at 908.4 MHz/916 MHz for the US so the signal is usually pretty good about penetrating things better than WiFi at least. The issue will be building a strong mesh so your devices can connect and route through each other.. Worst case is you "could" go to a multi-hub config if you really needed to but in my experience with that kind of sq ft. you should be okay. I have a client with a 3600 sqft colonial 3 story house built in the 1890s and one C-7 is serving the main house just fine (most every switch is a smart switch). I did have to go with a second hub for the detached garage though.
https://docs.hubitat.com/index.php?title=How_to_Build_a_Solid_Z-Wave_Mesh
Do you have any Apple Stuff? If so you might consider setting up a "headless" companion server and running HomeBridge.. you can expose your HE non-homekit devices TO Apple Home so they can be controlled by Siri and automated via Apple Home. You can also hook up your Nest and Ring devices as well. Unfortunately there is no way to control Homebridge or Apple Homekit devices in HE - to do that you would need to install another piece of software called Node-RED connected to HE OR set up a secondary smart hub server called Home Assistant (Warning! potential time suck!) and use the integrations available and bridge the HA devices to HE.
