JAVA!
Having finished a simple first version my JavaScript project, I decided to go full Java. There is no compelling argument to choose it over C++, although I like the fact that there are many jobs in it and that there are established certificates that might be helpful.
Regarding the latter: I spoke to people of House of Beta, a large recruiting firm that also offers traineeships, not so much in hardcore programming as in data science, cyber security, IT service management etc. They have a large network in government, the financial sector and the energy sector and thought that having a Java certificate would be beneficial.