Either build a startup around ML in Africa or get a job on completion of my studies. So wanted to hear opinions from people in the field or doing this already.
If you get a full scholarship then probably, that's usually the case though. The PhD will give you prestige and credibility if you start your own business, and will open some doors when you are looking for a job (but also close others). It will also set you back a few years from your goals, and the amount of money you will get with a PhD won't be more than with a MS. Best perk of having a PhD is working in academia, which can be a great life style: much lower stress, decent compensation, lots of vacation time and recognition.