Two things I found were just how fragile was the "Special Relationship" and how complicated as the path of Japan to its conquest of Asia. If the USA does not intervene in the Great War and did not have a true threat in Hitler later then I am not certain the USA would not find the British Empire quite intolerable longer term. Once Germany is contained to the continent that threat to America becomes more commercial, but there might be opportunity to cooperate that shifts the USA from a sweep Germany to face the British move to a use Germany to pin the British tact. Here I think the Anglo-Japanese Alliance wedges between the USA and the British, have that last through to the late 1940s and you have a potentially very anti-British USA. Recall the British handed the German Pacific islands to Japan in order to weaken the USA in Asia, the British here should need Japan longer and give her more support. Of course it should hit rocks in China but that may not go invasion of Manchuria, I think it is China reasserting itself, so maybe the later 1940s or 1950s here.
I think this Germany is going to take some time to get back on its feet, it should be focused in Europe for a long time. Russia likely plays more like Weimar. The Anglo-French should be rather unstable as each views themselves as the top dog.
And yes I think the USA would promote a sort of anti-Imperial league. They become the "third" way between the British and Germans as the single biggest economy, second biggest if we measure the Empire as a whole. Again I think the oil in Arabia might be another wedge, the Americans and Germans trying to push out the British, the Ottomans play all sides against themselves, a dangerous game itself.
You could break a lot of tropes as well as play a few to their end.
Britain and Japan kinda just lose touch because of differing governments and politics. Mind you, the American-British relations are pretty cool, but the Americans are okay with letting the British take care of rebuilding Japan once the paperwork is done and the Kyoto Trials have gone. The US do get some form of payback though; they take Hokaiddo and make it into a protectorate (a politician's son was among those with Hokkaido resistance fighers, mainly the Ainu and so uses his inlfuence for the idea.) This actually does influence the US to re-examine their behavior with their natives and actually be nicer and commit to the treaties better. Pacific War occurs a bit earlier than WW2 and US gets involves sooner as well.
American-British relations don't hit the curb until the thing with Iran and Britain retaliating with getting South American states in their sphere.
Here's how South America is on the three blocs:
Mittelmachte: Argentina, Uruguay, Paraguay, Bolivia,
Entente: The three Guianas, Brazil, Venezula, Ecuador,
League of Nations: Columbia, Peru, Chile,
The Mittelmachte is focused on consolidating their gains. Germany installing loyal rulers in their new vassals, trying to manage Mittelafrika and other colonies they got from France (French imperial empire in a few ways: North africa become vassals to the Ottomans, central Africa goes to Germans, the west coast may or may not go to Austria (that or the Germans just make them into their own or divide it differently. Maybe even remake the Toucouleur Empire
. The African allies get some land, so Darfur gets Sudan and the Dervish State gets British and Italian somalia. Italian Eritrea is kinda left by itself, but merges with Ethiopia.) Germany is just working on keeping order; their South American affairs are just them continuing their positive relationship with Argentina and the others while figuring out what to do with German Indochina.
Oil won't be as big here (there's a big explanation as to why, but no spoilers) and most of Arabia is in Mittelmachte control since Rasheed Arabia is part of the Mittelmachte. Oman just becomes a more British fortified place. It's notable that Ibadi Muslim becomes more widespread as a result, dominant in British East Africa because of Omani assistance.
As for the rest of the Pacific, the US refuses to let the Dutch have their colonial empire back, so the Dutch remain either neutral or eventuallu join the Entente. Nusantara is formed instead of Indonesia. Also, Philippines gets some oversight from the Mexicans because of language making it easier since the US will be looking at Nusantara.
But yeah, US relations with Europe aren't that good. They gave the Swiss an honorary seat at the League as a show of respect and they're pretty okay with the Nordic nations (Finland manages to make Karelia and Lapland free with them as part of the Russian Revolution.)