Questions about Ubiquiti U6-Mesh WiFi 6

Yes, that works and that's how I have it running. My U6 mesh is connected directly to a Ubiquiti US8-150W POE switch. The only disadvantage is that when the switch updates and reboots, the Wi-Fi also goes away.

You cannot combine the U6-Mesh WiFi 6 (4800 Mbps) directly with your existing AmpliFi Alien Router + Meshpoint to operate a unified mesh network. The two systems are not compatible and cannot be controlled together as a mesh system. You can only operate the U6-Mesh WiFi 6 (4800 Mbps) as a stand-alone access point if you integrate it into the network separately, but not as part of the AmpliFi Mesh system. For a standardised mesh network, you have to stick with AmpliFi or switch completely to a UniFi system.

Perhaps the Ubiquiti UniFi AP-AC-M MESH could be an option for you.

Yes, there is one, see also the manufacturer's website: https://eu.store.ui.com/eu/en/category/all-wifi/products/u6-mesh But when you write "to a... router", then I ask myself whether you understand how these access points should actually be used, namely in conjunction with the Unifi Network application / controller, at least at the beginning for the initial configuration. Just mentioned for the sake of completeness. Connection to the router directly is of course possible, but you have to configure the WLAN SSID etc. somehow. However, you can also use the Unifi app, you don't necessarily have to have the controller software running or even let it run.

Hello, all the products I have bought from Ubiquiti so far work excellently. The manufacturing quality is comparable to apple. Best regards from Stuttgart!

Yes, of course. That's how I integrated it, because it just looks really good visually...

one time with PoE (Power over Ethernet) - one time without, but the third, I can't explain either.