I would have thought that the best approach was both. Learning by ear to survive real life and also notation / theory to learn things that you cannot directly listen to, and to communicate with others
I point you to the work of Duck Dunn, watch the two Blues Brothers movies and you can see a groove genius at work - his work is simpler to learn than James Jamersons and more groove than funky imho.
before I get flamed, I hugely admire both of them
I’ve never left it, but with your last paragraph you are straying to The Dark Side and I urge you to avoid it like the plague
Yoda would be proud, stick to the righteous path of bass, avoid the six string w**kery