I currently have two APX530 units and am adding another access point model apx120 - my question is what is the range in square feet of the 120 model? Can’t find anywhere
Range in terms of Wireless are rare to find as they are highly depending on the current setup and the environment.
Most information are shown here: https://www.sophos.com/en-us/medialibrary/PDFs/documentation/sophos-operating-instructions-apx-120-oi.pdf
To further Lucar's point^ Every environment varies for range for both 2.4 and 5GHz bands. Things like building materials and other wireless networks cause interference so it's hard to give a definitive answer.
We put together a great article and video talking about Wi-Fi Fundamentals in depth give it a read/watch: