How much will the installer charge you per year for support ?
In general, I would expect minimum support for the setup if you are only charged during installation of the kit.
In terms of longevity of the setup, the most important thing to get done is a good cabling setup with quality cables and good camera positions.
Technology advances quickly, more AI features are getting added to cameras and NVRs. The NVR on your list looks like an starter NVR and has limited support, you may want to get a better one.
Your installer / CCTV contractor should be able to get a wifi camera that meets open specs like ONVIF to stream to the NVR. ( you can also search the various threads here on that topic .. )
If you have too many WiFI devices or neighbors with a lot of WiFi devices who are close enough to interfere with your WiFi you will have challenges as noted by Wittaj
Remember to test the positions before installing cameras .. many installers do not care enough to ensure a good position for best results, instead they focus on getting the job done with minimum work for max payout.
he gave me a quote of $2300 canadian. that includes the NVR and 3 cameras, but he's given me another camera option which I have to look at first. but I did notice that the depth of field of this camera is a little over 3m. so that might be fine for an overview of the property, but it won't be good for a camera at the entrance of the house. so I have to talk to him about that. I will also look into getting a better NVR because I think the combination of camera and NVR won't give me 4k video with 30fps which is what i'm hoping for. I think he said he uses cat 6 cables for outdoor use, but I'll have to double check.