A little tip about GOLIATH: The entire hardware is from "alhua", the other distributors just print their name on it. If you buy the original, you pay almost exactly half!
Good cameras for outdoor use cost money. And you should not underestimate how much data accumulates daily when the cameras record in a reasonably usable resolution. For one camera, > 500 MB per day is not little if it is set to be sufficiently sensitive. That is already the second topic: If you don’t want to constantly see bushes and trees moving in the wind, the camera should have a good person/motion detection feature. And who wants to evaluate 1,000 images per camera per day? Night vision also plays a role if you don’t want to install several cameras (day/night) right away. In my opinion, Wi-Fi doesn’t work at all because simply too much data needs to be transferred. A LAN cable or other hardware should be available.
It also makes sense if the cameras can be controlled quickly and easily via a monitor of the doorbell system. If you first have to start the computer, open the browser, enter the IP address, and so on, that is too complicated. One push of a button on the surveillance monitor and the individual cameras must be available. Dome cameras with remotely controllable lenses (rotation of 359 degrees, tilt angle adjustable, zoomable, etc.) are great. But that costs money again. A manufacturer with modular cameras (body, lenses etc.) is Mobotix, they have the full range from zoom, panorama, day/night to thermal cameras (even bulletproof). But then you are quickly in the four-digit price range with such manufacturers...
For the ambitious DIY enthusiast, I would still calculate about 180-300 EUR per camera. Below that is simply just a toy. Then better only one camera in a well-chosen location that works well day and night at all temperature ranges, is tiltable and zoomable ;-)