When you buy an EV in Germany, you gat a few advantages from the state, such as the €4000 refund on the purchase price. Strictly speaking its €2000 with a matching €2000 from the EV maker. This is in addition to any other discount you maybe able to negotiate. I didn’t need to negotiate, our dealer gave a very fair price without asking bringing the car about €7000 below list price.
You also get a 10 year no road tax period. The strange thing is you still get a tax demand payable in 10 years time by direct debit. I have forgotten how much the demand is for, I think something silly like €10 or €50. In any case, I doubt in 10 years time we will still own this car.
Additionally you can get a numberplate with an E at the end. In some areas this gives privileges such as free parking or bus lane usage. The only problem is this is regulated at the local, not national, level, so you never know whats allowed or not. So in practice, there is little advantage in having an E plate, but at least there is no extra charge to have it.