To many majors, the 6th HKDSE subject serves as a better alternative. For example, if your geography is better than Chinese History, the universities count geography and exclude Chinese History for you. You have eliminated this option by yourself. So you must do well in HKDSE for a chance in JUPAS.
However, based on your information, it seems that you have a problem in English. In this case, your estimated HKDSE result for English will not more than 4. This is the actual minimum for JUPAS admission.
Since your chance reaching this level is slim, you will mostly end up with a sub-degree program.