Sorry to point this out to you, but teenage airline pilots are actually a really bad look with the travelling public. Not too many operators in Africa are going to turn a 19 year old kid loose in charge of a C206 with a half dozen wealthy tourists on board, either.
The mere fact that you are 19 years old with an FATPL tells me two things ... 1) you've never had a real job, and 2) all you've done since you left school was train as a pilot. Nothing intrinsically wrong with either of those things but, from an employer's point of view, it is a very large flag that the guy probably doesn't have a clue about how the real world works. The fact that you're complaining on here because your job search so far has consisted of posting 25 CVs to random operators, is also a big flag that you REALLY don't have a clue about how the real world works.
There is such a thing as "too young" as well as "too old", and right now you are at a massive disadvantage compared to guys 5 or 10 years older, who have at least been out there, done some stuff, gained some maturity.
Want my advice, pack your bags and go travelling - in a country where you have the legal right to work. Go find a town where your target employer is, buy some beers for some pilots and get the info you need.
Alternative plan, get a job, even if it's not flying related, but something that will pad the CV a bit. Keep your IR current and keep applying. Don't get despondent even if it takes years, you are only 19!!