I have a long-term German National D Visa for research.
I have an upcoming short trip outside Germany to the Schengen Zone but I don't have a residence permit yet. I've been informed that I should get the residence permit before travelling abroad but that is contrary to what I've been reading online i.e. the D visa can be used for short-term stays in European countries outside Germany. https://visaguide.world/europe/germany-visa/long-stay/
Does anyone have experience regarding this issue or can tell if I am allowed to travel outside Germany?