Condensate - how to close the gap between the outer wall and insulation

Hello everyone. With our pipe insulation for the ventilation system, condensate forms between the insulation pipe and the exterior wall. Below are a few pictures. You can also see the droplet. There is a gap between the insulation and the wall. If I push the pipe closer, which would be minimally possible, the condensate (or whatever it is) runs down the wall. That’s why I have left it as it is so far. The last picture with the large gap only caught my attention now; it is in a corner where it is hardly visible. That is where the supply air is. Although no condensate has formed there yet, I still want to close the gap. Do you have any idea how I can best close it? I don’t want to work with foam or anything similar as that would probably be an optical disaster, thanks. I am rather thinking of some type of liquid insulating material from a cartridge or similar.

To my knowledge, the controlled residential ventilation pipes installed inside the room for supply and exhaust air are exclusively made of insulating material (rigid foam) pipes. Only the stub pipe leading outside is a "KG pipe". The condensate will then form on the KG pipe (the coldest point in the room). If you push the controlled residential ventilation pipe installed inside the room further over the stub pipe, it will no longer be cold inside the room, and the condensate should not occur? Ever tried that? What does the installer / plumbing company say about it?

With us, the black insulation pipe is installed continuously including the outlet on the outer wall.

An iron pipe has been inserted into the wall breakthrough and the insulated pipe is then fitted inside it.

: I tried to push it on briefly. However, that didn’t work because the pipe clamps that hold the line under the ceiling are too tight. I can’t move the line at the moment because of that. I need to take a look at how to solve this.
Let’s not talk about the incompetent plumber. We had several defects and had to set deadlines that he also didn’t meet. The work (not the affected pipe) was completed elsewhere.