As explained in my YouTube video below. Most of the chords for this genre you hear tend to use a lot of the black keys. You may not see too many players using only the white keys for this genre of music. However that does not mean they can’t be used. If fact any scale can be used, it is just a matter of how the chords are used.
For the piano, the C Major scale is the easiest to learn. The reason being is that it consists of all white keys only. However playing standard chords in the key of C only, may not sound too soulful.
A good method I like to use is having the 13th key as bass note instead. This gives it a whole new flavor, and is easy with the C Major scale. All do you is simply count from the base key to the right for 13 steps. For the C Major chord this will be the key “A”, so instead of of playing “A” on the right, play it on the left, one octave lower than the chord. Incidentally, the chord I would play (now with my right hand) would be 7th chord, C Maj 7th in this case.
As per the above diagram, The “A” 13th note would be played as a bass note instead. No need to play notes D or F. And use this same practice for all chords.