80MHz channels are never recommended in high density areas, indoors or outdoors. Are you providing free wifi to guests? You will still be providing 11ac even in VHT20 mode (e.g. higher data rates). Just not the highest possible.
In high density areas you want to provide more small channels in more places, not fewer big channels in more places. Because - as you are finding - RF travels a really long way and so none of these APs really is isolated from the others.
But back to your specific issue. Your last comment re-2.4GHz suggests the client doesn't like 5GHz for some reason.
Have you verified that the camera is using the same channels as the APs? The camera probably treats channels 36-48 as usable for instance, while the AP275 will not because those channels cannot legally be used outdoors in USA and 275 is an outdoor product. That could be producing a mismatch.
Since we don't have DFS approvals yet for AP275 you won't have a mismatch on channels 100-140, but this is something to look out or in future code upgrades when we turn this on. (e.g. if the camera cannot do channels 100-140 then it may not see the AP).
Yes you can create per-AP SSIDs. Easiest way is to create separate AP groups for each AP with custom VAP profiles. There is a way to do with it AP-specific config but that is tedius. TAC can help you either way.
The camera should be connecting on 2.4GHz to the closest AP even if it cannot see the 5GHZ. You may need a protocol analyzer or spectrum analyzer to figure it out.
Even if you are in a bowl, you may have other unlicensed systems in 5GHz.
-cl