When I go to "Network Connections," "Wireless Access Point" is not a choice (just Network (Home/Office), Broadband Connection (Ethernet Coax) and WAN PPoE). However, when I click on "Network (Home/Office)," then I can select "Wireless Access Point" and we're back on the same page.
My "Wireless Access Point Properties" screen is the same as yours (except it does say "Network (Home/Office)" where yours says "Broadband Connection").
But when I click settings, and switch the network from "Network (Home/Office)" to "Broadband Connection," I do lose connectivity and have to connect to my router via cable to be able to get back to the settings.
MI424WR-GEN3I, Hardware Version I
Frankly, I think my problem is related to my computer and not the router (because I can cast from my tablet and even mirror my screen from the computer - I just can't cast a single tab by itself).
Google reps quit responding to emails, so I believe I have them stumped.
Thanks for the help.