Did a diy bracket to mount it near ceiling. As I can’t hack the wall. I think this is the best solution d, although it look not very nice

wifi device

this wifi device just broadcast wifi.. not doing any routing job.. so yes, u need a router...
mostly general consumer device are wifi router.. and they gives a lot of different in terms of 2 in 1 job instead of specific job...
*based on my own personal experience and testing for comparing...

better coverage and more stable.. yes...

Different model with different price range. Can check online the price lelong, lazada.

If you want use at home. UAP AC Lite just do.
If you want cover more coverage, get UAP AC LR / UAP AC M (more recent product) - antenna can be customized to provide more coverage
If you have more recent devices (any hardware with dual band support 5Ghz) and like watch movie over wifi / streaming / upload video, get UAP AC Pro (better bandwidth for 5Ghz)

as for me, i am using UAP AC M. Easy mount i use double side tape to stick it on wall

no prob....not all familiar with ubiquiti... community grow, then more new things..

This is an AP