Ubiquiti can do everything, but it doesn't have to. The one I linked above just does Wifi. The one I have at home is a Dream Machine Pro. That is a dual-internet capable business-grade firewall with all the fittings, plus WiFi management, plus cameras and phones and door control and all kinds of other stuff. I got the one I did because here it isn't hard to convince the ISP to let you plug your firewall that you own directly into the fiber coming into your house, without any of their gear involved. This is awesome if you can get it, but doesn't support legacy stuff like cable tv.
The one I linked to you will work with any internet provider and any router they provide. It leaves everything else in place, just offering better WiFi equipment. It will work much, much better if you are able to get into the ISPs unit and turn off their wifi. You can leave everything else how it is, and stuff should continue to work, but reducing the number of radios needlessly broadcasting around your house is always a good thing.
The second AP can be wirelessly meshed to the first one, but if you have network cabling running to that room, you will see much better performance with them both wired in.