It is a transferable skill. But not one many people want to pay for except in very niche areas these days. So if you are out of a job expect to grind for awhile trying to find someone to hire for C++. Unless you have network connections then you might be ok. Being good at C++ only goes so far, you have to have skills in techs people are willing to pay for. Not many companies are willing to wait while you skill up in their stack unless you are willing to work jr but they will not hire you anyway because 'you will jump ship'. Its not great.