SpaceX used to pay AS33891 Core-Backbone GmbH to reach AS3320 now they pay 1299 (German (landed) Starlink users) for that
Interlink is to get to France Telecom/ Orange from German Starlink users
And to get Italian/Bulgarian landed traffic to AS3320
From what I see most of the traffic that flows via inter.link from SpaceX is point to point traffic. Not regular IP transit like what they get from 1299 or GTT
SpaceX is settlement free in Germany, customer elsewhere.