configure old airport express

I have an old Airport Express (802.11g) that I want to set up as an open network, so I factory reset it, but the current version of Airport Utility (both iOS & Mac) won't work with this older device, and the older version of Airport Utility won't run on Catalina. Is there a workaround? I can connect to the router with a Windows PC, but Airport Utility for Windows won't run at all, and the whole point is that I want to be able to connect Apple devices to it.