If they had just defeated Britain and France making them to accept a peace treaty, NZ would be legally bond to it and Japan would have to comply, otherwise they would face world’s 2nd largest navy.
If I recall correctly, Germany's existing battleline was heavily optimized for short-range missions in the North Sea, because the pre-WWI German ship designers weren't stupid. They were perfectly well aware that if they couldn't win battles in the North Sea, it didn't matter whether their dreadnoughts could fight a battle at the end of a ten thousand kilometer voyage anyway; they'd never
get there. While I doubt the Germans would fare as poorly as the Russians did if they attempted to retrace the steps of the Voyage of the Damned, they would face many of the same problems in projecting power into the Pacific. Britain and France might not be shooting at them but certainly wouldn't be
friendly, and refueling the fleet
en route could be a serious problem. The High Seas Fleet never got much actual experience on long range sea voyages; I can't comment as to the mechanical reliability of the ships when out of their home port for months at a time, a condition they were never designed for.
And at the end of it, the world's second or third-largest navy would face the world's fourth or fifth-largest navy. Which would be well prepared, operating an order of magnitude closer to its bases of operation, and probably informed as to the exact composition, whereabouts, and details of the opposing force by sympathetic Englishmen and Frenchmen.
Moreover, the Japanese could with reasonable confidence concentrate
all their ships on meeting the Germans, whereas it would be, ah...
bold... of the Germans to send the entirety of their fleet off into the Pacific Ocean to fight the Japanese.
This is a prospect that a sensible German government would view with great caution. Giving the Japanese a reasonable chance of pulling off a second Tsushima, less than a generation after the first one, could turn out to be a
huge unforced error for them.
Of course, high on military arrogance and victory disease, a government might not be sensible- but I can't say how that would turn out.
I guess it depends on how German and Western racial attitudes evolve. As I tend to be optimistic, I guess they could have evolved like OTL or even faster.
Regardless of German racial attitudes, they were
not gentle colonial overlords. Ask the Namibians.
In this case, we could have a situation similar to the British, French, US colonies today, with relative weak independence movements.
I'm not sure what you mean by "similar to the British, French, US colonies." Could you expand on that?
The set of all former British and French colonies, let alone all US ones, covers a pretty wide range of different places that saw different outcomes.