While true these weaker one are NOT causing the infection, they simply die and are forgotten. However if a viral particle is capable of infecting then it is viable. Whether from the surface or kissing then there is NO difference in the genetics. There is no "weak virus capable of infecting someone and creating a lesser infection".

The data is showing that there is very little difference in ALL of the viruses that have infected folks across the world which include all routes of infection including from surfaces and aerosol droplets.

Now there can be a case made like Charles said that the initial quantity dosing can effect our immune system ability to fight it off. This again reflects the host ability and not the individuals virus capabilities. Even so this notion is not proven at this time for this particular virus.

The notion that it is better to get it from a surface a few hours old is not appearing to be the case looking at the genome structure across the world. We would be seeing a much degree of variance in genome structure if that were the case.