Basically road pavement damage is proportional to weight of vehicles that run over them (and - to a lesser extent - to the amount of vehicles).
Having more electric vehicles actually increases - on average - the weight of cars, and - indirectly - road damage (how much is to be seen in practice).
For commercial fleets, trucks are already so heavy that - as you say - provoke the most damage, but they are heavy because they move things that "you/we" need or want, and that "you/we" actually pay for in the end.
So, if there won't be any more income from gas-guzzling cars, and taxing the electric cars is politically not viable, what remains is that the costs will be put on comnmercial transport, which means ultimately that final users will pay more, much more for transport of the goods they buy.
The traditional approach was to tax indirectly (via car related taxes) the - in theory - more affluent part of the population (that could afford to buy and maintain a car), if this source of income ceases to exist, the only way to replace it is to tax more "what remains".