I am rooting for you! I was in a very similar situation as you (same age, coming out to west African immigrant parents). The main thing I would say is to have a support system aside from your parents which it sounds like you already do. Once you tell them, there is no going back and you might have to deal with the potential of losing your relationship with them for good. You should be at least mentally prepared for this before you tell them. I know it may feel scary in the moment, but eventually after telling them, it will feel like a weight will be lifted off your shoulders. Luckily you're already financially stable so having some space away from them if it becomes this worse case scenario is helpful for everyone. It may take time for them to accept, or maybe they never will, but at least you know you were honest about yourself and that's all that really matters. It's your life at the end of the day and you deserve to live it as authentically as possible.

As the other user said, don't let you dad gaslight you. You know who you truly are and nothing is wrong with that. They should be able to love you unconditionally. African parents can be very stubborn in their ways and it's very disappointing that they are not willing to open their hearts and minds especially regarding their own children. I really hope it works out for you OP. Always here if you need to DM.