object oriented languages (like Java, C++ etc. ) cannot be used to program controllers
Rubbish. You can do anything in C++ that you can do in C, and a great deal safer. I speak from much experience. People often confuse C++ with more "automagic" languages like Java and Ruby. C++ has no garbage collection, and if you want to manage memory allocation yourself, including doing everything statically, it's easy. In 2020 doing any major new code in C is a sign of insanity. Of course if you already have a legacy of 10 million lines of C code, like my erstwhile employer, you're a bit stuck with it.