A few months ago, I started studying how people monitor luxury real estate listings in Dubai, and the difference in results was striking. When filtering for penthouse listings, volume drops quickly, so setting a narrow alert radius of two kilometers around the target area is very helpful. Each area of Dubai behaves differently, and, in particular, with penthouses, listings sell within a few days. For example, check out information on penthouses for sale here
https://atvir.com/uae/residential-complexes/penthouses