I'm no expert on Rap - probably my most hated type of music, but - although I really hated it, your voice doesn't sound wrong - and to me as an absolute Rap detester, it annoys me just as much as every other rap tune I hear. So I guess it turns your worry into a positive. If your voice was wrong, then it would have jumped out to me, even more - so I reckon you should look upon this as a success. To me, a total non-expert, it sounds the same as other stuff I occasionally have to endure.
Looks like you've got a handle on the style, and your voice works.