“Musical talent” is not how anyone gets good at an instrument. Some people can get better a bit faster, some do it slower, but absolutely everyone without exception has to put in the work if they want to develop the skill. The only reason Lil Wayne plays guitar like he does is that he never learned much of how to play guitar. The fact that he knows a lot about other aspects of music does not change that. But what he plays seems to make him happy, so maybe he doesn’t need to learn any more.

Similarly, I’m a terrible violinist. I’m a good guitarist, I’m a competent bassist, and I know my music theory to a decent level. I’m still shit at violin because I haven’t practiced enough yet. You could have the musical prowess of Mozart himself, you’ll still be shit at guitar when you first pick it up.

Knowledge of musical theory helps, but you have to take the time to learn that anyway. Playing other instruments helps your sense of rhythm and your dexterity, but you still had to take the time to learn them. The only shortcut is if you have already done the work on a really similar instrument, but the point is you had to do the work on the first instrument.