First of all you got to have a fair amount of light where your car are parked, and since its eggin ( not a known thing here in Denmark ) then i assume it are done from some distance.
And dashcams are not really the best for things at a distance as they have a wide angle lens that make things appear in the footage as it they are even longer away.
If its at night and people are 20 feet or so away ( 3-4 car lengths ) then you will not be able to use the footage for much unless one of the punks wear some bright clothes that's easy to recognize.
I had my cars vandalized 2 times after i moved here, first suv got keyed along one side days before i sold it, making me have to take a dive on prize, my new car then got the Right front door window broken for no reason ( nothing stolen )
So now i park in the pitch black back yard behind the apartment block and have a 1080p IP camera on the car all the tile ( IR light aided when dark )
And still i have gotten my car vandalized again, but this time a D cell battery was thrown high in the air and then hitting the roof on my car making a dent.
Only noticed that after a few days where i was ???? why is that battery lying there ( dent on back Left corner of my roof ) but i finally saw dent and added up 2 + 2
But this arnt really on any footage , at least not the battery getting thrown as i am zoomed in pretty tight on the car where its parked.
A IP camera with some zoom, and a 4 channel NVR recorder + a harddrive are not cheap, but in this case the only useful solution.