It really looks like some Bach parts... but perhaps not. Obviously has a small kranz on the bell much like some Laetzsch horns, but I've never seen one of theirs with a Hagmann. Slide looks like it doesn't have a Bach crook or ferrules, either.
Kromat would also have been my guess. Great quality instruments, somehow Bach-oriented with some added German DNA. I am pretty sure they could build the "perfect Bach" if only they had any time left. On the other hand they could certainly also play a more German instrument. They have been very very popular now for many years. I know multiple people who bought one in the last years. Stefan Schulz played it for many years even while officially being Courtois artist.
I followed the ARD competition and also had heard some recordings before. Really great trombonist who will certainly leave a good footprint in Berlin. Somehow it was obvious that he or Kris Garfitt would win the ARD competition. Kris Garfitt may have a bit more soloistic character while Jonathon Ramsay for me showed more orchestral approach and sound. Both 10 times better than what I could ever have reached