What is the right course of action here?

Your answer is correct because according to German traffic rules at an uncontrolled intersection, priority is generally given to vehicles coming from the right. Here, you are in the position to go straight, and neither the cyclist on the left nor the red car on the right has priority over you.

The cyclist on the left must yield because you are not coming from their right, and the red car turning left must give way because you are driving straight ahead. So you may proceed first safely.

This rule helps to maintain order and avoid confusion at intersections without traffic signs or signals by giving priority to the vehicle on the right.