Sweden will not pay curtailment fees, such a thing does not exist. The reason is exactly what you quote at the end.

To state it again:

1. The intranational powercables means that German demand raises electricity prices in southern Sweden, which means businesses and consumers pay a premium vs what they would have paid without the cable

2. The extra charge is captured by network operators as what is called bottleneck fees and it's billions of euros per year, very large sums

3. The EC first wanted to confiscate these funds, which come from Swedish consumers and businesses. Now they want to rule about their use. Obviously this is completely unacceptable and nothing more than a bureaucratic powergrab, and no country would accept it.