Maybe give this Italian flight school a ring. Shame we can’t read the OAT on the PFD, but must have been pretty low. Bristell UL with shroud heating.
The certified Aquila A210 also has the classical exhaust shroud design, and both cabin heat and defrost work well. This includes the -18°-weekend.
Additionally, the material of the exhaust and shroud seem to be good as well, we never had a problem with corrosion or cracks, as opposed to the systems on the more traditional Lycoming and Continental engines.
So the problems you apparently have with your aircraft seem to be airframe-related.
