Access Point Advice

Hi I am hoping some more knowledgeable people may be able to help

I am wanting to purchase some Unifi equipment for the first time after being on wifi routers forever

I have 1gb fibre broadband and live in a 2 bedroom upstairs maisonette/Apartment/Flat

I currently have two WiFi routers running with one as my main router in the lounge room and the second at the other end of a 20 metre cat 6 cable in the home office a couple rooms away and the second WiFi router is in AP mode

A hallway and bedroom are in between these rooms

Due to my connection speed I am leaning towards just getting the cloud gateway ultra as I don’t see myself increasing my connection speed anytime soon

Most of my devices are on WiFi which includes some Tapo smart bulbs and security camera as well as Alexa devices

And then a couple MacBooks and iPhones and windows work laptops

I am wanting to get some AP’s to run off the Ultra but due to renting I cannot router cables through the building my 20 metre cable mentioned for a wired backhaul is under my carpet down the hallway from the lounge room

I don’t particularly want to have a visible cable going right up my wall so was thinking of either

Looking at a desk mountable option such as the u6 mesh

Or wall mounting another AP either one of the wall ones or regular puck shaped ones but mounting it lower so I can try hide some of the Ethernet partially on the wall

I am however concerned about how well the AP’s will perform seeing as they are meant to be ceiling mounted

Can someone help in confirming if the AP’s will function and provide strong wifi in a room if not ceiling mounted and instead mounted perhaps vertically on a wall?