Plummeting world Wide you say.
Compared to two years ago, yes. It's not over yet, not by a fair way, but it's definitely over the hill and heading down quite fast.
Peeing in cornflakes might play well in the rustbelt, but if you look at the EU now they are planning for a future without US involvement. If you look at China, it is planning for a future where it tells the US which parts of the Pacific it can still use, and how much steel will cost it. If you look at Africa, it's dominated by Chinese investment and soft power. If you look at the Middle East, that's back under the Russian sphere. If you look at Latin America, they hate America's guts even more than before.
Trump's policies are isolationist. That means withdrawing from global influence. The USA is now not the dominant power anywhere except North America, and its reputation has nosedived in the past 2 years (just look at the approval ratings in most of Europe, especially the key allies of UK, France and Germany).
and then Germany turns around and pumps Billion$ into Russia's economy by buying your gas from Russia instead of one of your allies
Hang on, isn't that exactly what Poland has been doing? Poland decries it, yet increases imports at the same time.
Re USA as part of the global economy, look at these graphs and weep:
First graph shows that China will overtake the US as the top economy in less than a decade.
Second graph shows that the US's share of the global economy has been declining for the past 15 years.
Fourth graph shows that China is already the world's largest trading nation, ahving overtaken the USA in 2011.
Whichever way you look at it, the USA has already peaked, and its time as the top global power are over.