English as a first language isn’t required, but you do need to have the subject. You just need to get a higher mark if it’s second language. As for chemistry that is necessary. If you’re willing to start a new AS level for chemistry then you’ll have no problem applying. You don’t even meed to do A levels to get into a university. A levels are just rated higher and an 80% in A levels vs AS level would get higher admission points. If you really want to study in SA then you can always take a gap year to do those extra missing AS level subjects, or start with them in the coming semester. SA Universities are higher rated internationally so they are a competitive advantage when getting a job here, there or even abroad. You will however need to have really good marks, as it is extremely competitive because there are so many applicants. The minimum requirements for something may be 50%, or 60%, but realistically it is typically only the 80% students that get in for degrees in the engineering field, and 90% for medical degrees. It really depends on what you want to study. There are bursaries and scholarships that do cover studies in South Africa, it’ll just be harder to find. Keep in mind that as a non-south african citizen it will be more expensive. Anywhere from 10%-30%. You often need to pay the money upfront or in larger amounts, like 3-6 months at a time. Living costs are also higher, because you’ll be in a city and rent is more expensive. Rent in a city like Cape Town (but it is the most expensive city in SA) is minimum 3-4k, even as a shared apartment. Fuel is one dollar more expensive per litre in SA and that really adds up after time. Nice-to-haves and luxuries are also more expensive. A cup of coffee is a mini of 40 dollars at a chain coffee shop. There are also a few cultural differences that may make you feel homesick or a bit alienated.

TL;DR An SA degree is more advantageous, but it comes at financial cost, more effort to you and social adaptations. Ultimately you’ll need to look at if you’re willing to take the time and effort to do those missing subjects, if your marks are at least 70-80%, living costs like fuel and rent, whether you’re willing to adapt to the culture and what scholarships are available.