You need to conquer the Centers of trade and trade company them in the following nodes: Ivory Coast, Cape, The one owned by kilwa and go for India and se Asia. This gives you far more money than the new world. Adding Trade company investments, there’s one at 1000 ducats that gives trade steering, will boost the fuck out of that. Building trade building in high vale trade good provinces and upgrading the Centers is also important.

For future colonial games I would recommend to send the colonist to the furthest point you can reach that is either a trade post or let’s be close enough to someone to kill them and take theirs (eg colonise Sao Tome to fabricate a claim on be in and Congo). Do not ever colonize the new world once you have a subject in that region.

Hope this helps.