If zoom is important to you, you should take the 823 x16.

I monitor a 260m2 hall with this 823, but with two cameras.
Then the normal 823 is enough.

10 m plus, thanks to high resolution, certainly more at night during the day

I use the 823A at a fairly remote holiday home in the mountains (mounted on a canopy at a height of approx. 3 m). During the day, with max. zoom up to approx. 50 m, you have halfway decent detail recognition. Of course, you can also see areas further away in sharp focus, just with less detail; it just depends on the specific application. At night, it mainly depends on the lighting. The integrated IR LEDs illuminate an area of around 20 metres.