Low CRI inhibits potential PPFD / red per watt same as high K, both by modifying the color ratios. Consider high CRI, red ratio is increased to satisfy a color matching system and will be true at any K value.
Not all veg lamp recipes have the primary goal of keeping the plants as short as possible. My personal choice would be 4000K 80CRI as I want more light in the +600 range being that it's the most efficient while 80CRI keeps the deeper reds to a reasonable level. Nothing wrong with full cycling a low K high CRI lamp but personal preference or space restrictions can change what is most ideal. It would be interesting to see a side by side of various veg only spectrums since most tests are more concerned with flowering.