I work in an embedded / safety critical software tools vendor and I can say C++ is pretty big in a lot of embedded spaces (maybe 40% vs 55% C, with 5% other) whether it is growing or shrinking depends on which industry (In avionics it is being displaced by model based design but it is growing in medical devices), I will say that the embedded space also has a lot of C programmers who via C++ as a bastardization if their beautiful language.

The general rule, with many exceptions, is that in lowest level embedded you see C with a healthy sprinkling of assembly, in higher level embedded (programs with guis or that just involve a lot of component interaction and interfaces) you tend to see C++

FYI, for a nice sampling of what C++ jobs are out there you can look at the C++ jobs posts at Reddit’s r/cpp