Unless you want a "reef blue" look in your planted tank, you need not add blue LEDs. The 20000 K that you have chosen (or even your previous choice of 10000 K) would impart the bluish tinge. Unfortunately, we can't find a common ground here to meet, so to speak, as I don't really care for that kind of look in a FW aquarium.
So far as your plants are concerned, they would get the spectrum they need to grow from your 10000/20000 K LEDs. The spectrum I am interested in is only for our own visual pleasure, which does not benefit the plants. One thing must be said in your favour. With the kind of light you have chosen, blue and red colors in your fish would really pop out, albeit at the cost of the "whitewashed" look of the plants.
I would, however, point out another drawback in choosing those lights. the PAR would be much higher as the lumens would be very high. That would drive your plants like crazy, and you would have to bump up your CO2 injection, more frequent fertilizer dosing and trace element addition and, of course, a lot of pruning. I am a lazy guy, I really can't take that kind of 'torture' LOL!