Only tangentially on topic...
To my mind a correctly configured, and up to date in its' software, commercial grade (hardware) firewall is far better protection than that provided by Microsoft's built into the OS (software) firewall. Given the current situation with ransomware and other threats this is a solution that may be worthy of consideration if your business depends largely on reliable internet service. Even this will not prevent lack of useful access to the internet if, for instance, a major DNS server is taken down, unless you and your customers are able to use the site ip address in place of the domain name.
That said, I've had little trouble with running very old programs on Windows 10 Enterprise. With a modest amount of hacking even most 16 bit programs can be made to run acceptably with no ill effects on the OS.
I no longer consider myself qualified to make a useful comment on the state of security in any Apple OS.