[The cyclist] wants to continue straight ahead. What is the right course of action here?

You chose to remain behind the cyclist, which is correct. In situations like this, where a cyclist is riding straight ahead and you plan to turn right, German traffic rules require you to wait and let the cyclist go first. Turning across the path of a cyclist is dangerous, and cyclists have the right of way when going straight. By staying behind and not overtaking, you avoid cutting off the cyclist and ensure everyone's safety. This follows the basic German rule that vulnerable road users, like cyclists, must be protected and given priority in such situations. Remember to always check your mirrors and blind spots before turning.