White light is vaguely made out equal amounts of 3 colors that our eyes can see, reb, blue and green. Lumens is a measurement of brightness to how our eyes see the electromagnetic spectrum, i.e. radiated energy, and our eyes see brightness mostly from the near green spectrum segment of light, which is almost useless to plants. So those lumen numbers may not represent the intensity of the PAR, or photosynthetic active radiation, available to the plant’s leaves.
As others have said, you can use one light the whole grow. 5000K-6000K is generally considered true white light, and sunlight is usually pretty much about 5500-6000 all year long, even in the winter. Below these numbers the light becomes more yellow, orange or redish. And above this number the light becomes more blue.
However plants need much more red light than they do blue light, only about 20-30% of the light need to be blue to keep your plants happy and healthy.
It is generally understood that plants use mainly/only the blue and red parts of light and that more blue light, and blocking a specific hue or shade of red, not all red, just a small section of the red spectra, prevents unwanted excessive stretching between internodes. And that red light is more important for flowering/fruiting. And so blue-er lights are used for veg and redder lights are used for flowering. Also vegging takes place outdoors during the spring/summer when the sun is more directly over your area and fall winter is when the earth is tilting away from the sun causing it to pass though more atmosphere not unlike closer to sunset, and this is when cannabis flowers out doors. One can easily see why these color changes might be used to replicate some changes in sunlight that occur through the different phases of growth.
Plants grown in all red light will grow to be overly tall and leggy and ones grown under all blue light may be low-growing and stocky. Overall, more red light is needed than the blue in photosynthesis regardless of vegetative growth or flowering/fruiting.
You can look into the exact specs about the lights from the manufacturer and determine eventually if you want to buy each light, but to start, I’m sure the 6400K will do well for you for all phases of growth.