If you need a utility to help detect which devices are on a wifi network avoid the free download Glasswire, and instead try MyLanViewer.
I tested them both out tonight. Glasswire was unable to detect iPhones and an iPad on my home wifi network and did not show the name of these devices and a laptop on the network - plus it simply has a very generic look.
MyLanViewer found and named the smartphones and tablet, as well as Google Home - but not Alexa for some reason.