In my experience, in a crowded single-AP situation, the most bleeding-edge grotesque looking Netgear Nighthawk you can afford will probably do better than spend

In my experience, in a crowded single-AP situation, the most bleeding-edge grotesque looking Netgear Nighthawk you can afford will probably do better than spending the same money on SMB/Enterprise gear. Ubiquiti UAP-AC-HD / UAP-AC-SHD reportedly do well in crowded space but I've no experience with those models. Disable 2.4GHz if you can. Use separate 2.4GHz and 5GHz SSIDs to force everything 5GHz-capable to that band. Use the smallest channel width. Use the lowest transmit power and highest receive sensitivity that gets the coverage you need.