You must not confuse three things with each other. Since the unbundling, there have been the Distribution System Operator (VNB), electricity supplier, and meter operator. The VNB is responsible for the house connection, and you cannot choose it. It is authorized by a concession with the local municipality or city to operate the distribution network. The VNB must have its prices approved by the [Bundesnetzagentur].
The price for 30m including everything is totally fine in my opinion and the rest is the already mentioned construction cost surcharge, which involves the connection user in the infrastructure in front of their house connection. Totally normal. Getting upset won’t help. If you want electricity in the house, you will have to pay for it.