From a personal view I think it’s extremely important to be studying subjects that you enjoy as well as subjects that can lead you towards a career that you will enjoy.
With regards to the “Asian 5” I firstly think these subjects are really popular because they’re considered “harder” (which I don’t really agree with) and also they lead to medicine and engineering quite naturally. If you are interested in medicine or engineering then it certainly makes sense to take these subjects because it will lead into your university study quite naturally.
I personally did Maths, Physics, Chemistry, Economics, Music and Drama in my last year of secondary school and I still have plenty of opportunities and career pathways that are possible. For example, entering into the business world, either as part of a corporate firm or in a more entrepreneurial way, are both possible options. Furthermore I could study humanities at university to develop transferable skills such as communication, critical thinking and logical reasoning.
If anything, I think you’re more likely to be successful in any future endeavours if you are doing something that you enjoy. Also, you’re likely to do better in the subjects that you study if you enjoy them, and your grades will often be more important than exactly what you studied, especially for competitive university entrance etc.
There are certainly many opportunities outside of medicine and engineering, and it’s important to look for things that interest you personally. Of course, you can always study subjects you dislike, but you have to ask yourself whether the work you will be doing after you finish studying will be enjoyable or not.