It's in the better be monitoring labwork and taking vitamin d cofators territory.

Under Dr supervision, daily vitamin d can be much higher. For example, the Coimbra Protocol for multiple sclerosis can be as high as 40k daily.

Yes, taking that much vitamin D every day puts you at risk of developing dangerously high blood levels. One of the things it can do is screw with your calcium levels which screws with your nerves which can, for example, make your heart beat abnormal.

Don’t do this without the advice of a doctor and regular serum level testing.

I expect the K2 would reduce the risk of calcium build-up, but it's still a very high dose which could pose problems.