A little more info now I’ve fully read your post: You have several options. If you have a permanent L and N at the light, you can just fit one Shelly there, and use the switch wire as a trigger.
If you only have a N at the light, and you only have an L at the first switch, you’ll need 4x Shelly’s. You’d join the L all the way to the lamp, and join the N all the way to the first switch. Then you’d have a permanent supply at each switch plus the light. Fit a Shelly behind each switch, and connect the switch to it’s inputs. Fit a Shelly at the light, and connect the light to it’s output.
Then you need to connect all Shellys together via wifi. You can either do this directly (device to device) or you can do it via the home wifi.
The function of each switch could be individually controlled, and the light can be switched on/off via app, timer, smart home system etc.
I am a professional CCTV installer and I would recommend against this.
Consumer grade home tech products are way too easy to hack (there are a few darknet diaries episodes about this but a quick Google will show you plenty of examples)
In the rare occasion that we install cameras indoors, we generally wire their video feed via the intruder alarm which means when the alarm is unset (i.e you’re at home) - the camera is off. Not just ‘not being watched’ but completely powered down and disconnected from everything.
I work in the industry and I wouldn’t have one inside.
It would be interesting to know why he wants one, there may be other solutions for him…