So, there was no point in switching over the phone app controller. But, when I replaced my old AP's with the new ones, my existing controller immediately recognized the and applied the existing settings to them. I think that you can use your phone as the controller. I don't think that you need to use a computer for this anymore. It's just how you can monitor and change AP settings. You don't need the controller on all of the time. At the time, you needed to use a computer as a controller. Prior to these two AP's, I had the older Unifi Lites in my house. I'm currently on their notify list for when the Unifi6 Long Range come back in stock. I bought them when they were the only Wifi 6 units that Unifi had. One in the basement and one on the first floor. I currently have two Unifi6 Lites in my house. The in-wall units also have ethernet ports, so they act as pseudo switches in case you need some wired access. If I were to suggest an AP I would say an in-wall WiFi 6. I have a normal network as well as an IoT network as an example. Each AP can output multiple SSIDs or can all use the same, depending on how you want to setup your network. This system will not work without a controller as far as I know Unless something has changed recently. Ubiquiti is doing a WiFi 6 rollout, so that may be less of an issue, and would take more research. Be careful though as they used to have different type of PoE than was available on most switches. These APs are powered by power over ethernet, so you either need a PoE switch or an injector. If you add additional APs they can operate in mesh mode, although wired is always better. To answer your questions directly, you can get by with 1 access point depending on your space. If you need additional access points add more in slave mode. I spent thousands of dollars on a system that has worse performance than spending a couple hundred on a quality router and separate access point. i feel like a beta tester that paid a premium to test these products. I still get daily controller disconnects, and i am not able to figure out why. All the help on the community page says that the best that I could possibly get speed wise was what I was getting with ubiquiti, but I could prove that is not the case when switching hardware to another brand. I can honestly say I got better wireless throughput with my old asus router than my UniFi stuff. I currently have 7 switches, 4 access points, 8 cameras, NVR, and USG. I am an electrician by trade, so I was able to run Ethernet throughout my house. I am not a networking pro, but I love to tinker. At this point when I add to my network I continue to get ubiquiti stuff, but only because I am committed at this point. I have had ubiquiti UniFi network since the end of 2017.

Unifi beta forum