First make sure Camect is getting the full resolution feed from your cameras. It probably is, but to check, open the camera settings and click the "i" next to "Camera Name". It will show you a bunch of details about the stream, including the resoution.
The resolution in the multi-camera view is limited to VGA resolution. If you click the "pop out" button at the top left, you'll either get to full resolution, or to a higher (but not full) resolution if your viewing device's CSS resolution is less than that of the camera. If you get an intermediate resolution, you'll be able to get a higher resolution by clicking the button in the location again. At that point you should be getting the full resolution of whatever is coming from the camera.
If it still looks bad to you at full resolution, then try exporting a short clip of motion. (Make sure the beginning and end markers are entirely within a region of light or dark green when you mark off the clip.) That will get you a sample of video as Camect is saving it. If it looks fine when you play it in VLC but it looks back when you're viewing in the UI, it would tell us that there's some issue with how the playback is being set up and we can investigate that more.