I’ve installed a bunch of AP AC Pro devices. They work well. The people who say they are junk are comparing them to full, high dollar enterprise systems. They’re low-mid range when it comes to business class. For small offices and home use they’re probably the best, most cost effective thing you can get.
I’d say stay away from the AmpliFi products. It’s not that they’re bad, but if you are in the market for mesh WiFi there are better solutions. It sounds like you want to go higher end than mesh anyway.
The APs are great. You hard wire them to a switch, any switch is fine but if you buy into the unifi ecosystem you can manage everything with a single control plane if you’re getting fancy and running multiple networks it’s helpful. The APs are powered by the switch. If the switch doesn’t provide Power over Ethernet it’s fine, there are little injector boxes that can go inline.
You also need a separate router. Again, you can do whatever you want. I just have a little PC with two Ethernet ports and Linux on it, but you can get cost effective routers from Ubiquiti or Mikrotik.
My home is three stories, about 8500 sqft and I have three APs. Two on the second floor on either end of the house and one in the basement. I could have done without the basement one, I had full coverage but wanted the higher 5ghz speeds everywhere. It was fine though for streaming YouTube and such.
There is also an LR (long range) variant that might be useful for getting you outside coverage, and actual outdoor APs if you desire. A lot of this comes down to planning placement and understanding where you have or can get hardwired.