U7 Pro XG

Saw your edit Hiding APs in your closet is probably fine for 5Ghz but if you are thinking of going 6ghz I would highly recommend leaving the APs visible and within the room you have your 6ghz device in. 6ghz does not transmit thru walls very well. I believe there are some in wall options with paintable panels, but I’ll say that the new UI XG APs look very good. Better than that smoke detector that’s hanging out on your ceiling right now.

I have a mesh setup with a XG Pro and a UX7 off of my Cloud gateway fiber and it just works. No issues with it for me. It allows me to be lazy!

I personally would get the UCG Fiber and the U7 Pro XG (or even the U7 Pro Max) the Pro XG has a 10gbe connection but without a 10gbe switch its not fully utilised. The U7 pro max has a 2.5gbe interface which would mate well to the USW flex 2.5 8 port poe switch. Even then the U7 aps might be too much if you dont plan to be using all that much bandwidth. 

I believe most routers will handle 30 odd clients/devices if theyre in range.  If you need more range in different areas ideally you would have multiple access points. Eg a mesh system. Multiple access points with a wired backhaul (feed back to main) is the best as its not sharing bandwidth with itself. I run a unifi system myself but that is more prosumer grade. If you want a more basic solution they have those as well.  If your internet connection is not very fast a better router wont help. What internet connection do you have? 

I use an Ubiquiti Cloud Gateway and have three Ubiquiti U7 Pro nodes on PoE spread throughout the house. It's been fantastic. Really enjoy the UniFi software as well

A whole home Ubiquiti setup sounds up your alley. If you run Ethernet throughout your house, start with two of something like the U7 Pro or U7 Pro Wall (depending on whether or not you have an easier time mounting to your ceiling versus a gangbox). Feel free to mix and match units, preferably keeping them both at a distance where most devices stay within -70 dBm from each on 5 GHz. If you need more than, say, 4-5 Ethernet ports from a switch and something like a Cloud Gateway Ultra (gigabit only), Cloud Gateway Fiber, or Dream Router 7 (this one includes Wi-Fi, so make of that what you will) is lacking for that, add another UniFi switch of your choice. The “Wall” UniFi APs have Ethernet ports as well. Do you have gigabit? Faster than gigabit? Have you run Ethernet throughout your home already? Do you currently have fiber or coax, and if the latter, do you have a cable modem already?