Krishna means dark. Krishna is called Krishna because he is dark.
Also dark skinned Draupadi is called Krishna.
Shukla means bright.
The Krishna Yajur Veda is the dark, the Shukla Yajur Veda is the bright Yajur Veda.
Shukla Paksha is the bright phase, Krishna Paksha is the dark phase of the moon.
So the term ‚krishna‘ does not necessarily have to do with God Krishna.