I said relative to the rest of the world

Yes, and I said that that does not seem to be the case at all. Relative to the rest of the world, Germany seems to have been in a much, much weaker position in 1930-1940s than the US now.
I welcome serious sources to be proven incorrect.

Back in the 1930s and 1940s, the only major military and economic powers on earth were France, Britain, Germany, the US and the USSR

And now, it's just the US (and the vassals that it controls), with no opposition from the USSR or a similar polity. The PRC does not seem to take any military action today the way the USSR and the PRC did last century.
So far, the US seems to be miles ahead of 1930-1940s Germany.

On the other hand, the military and economic differential between the US and China is obscenely unfavorable for the US.

Firstly, the PRC hasn't been taking any action to beat the US and to liberate its colonies so far. It doesn't matter if the PRC has a better military (this claim seems to be untested, given no recent experience of the PLA fighting), and/or if it has a better economy if it's not going to be used to fight the US.
Secondly, the PRC and the US seem to have militaries of rather similar sizes, with the US also having the rest of NATO to back it up and with the US also having a military with recent experience.
Thirdly, while the PRC has much greater actual productive capacity, that productive capacity is used in large part to supply the imperial core with the produced goods. The productive capacity of the PRC is thus, effectively, in part, the productive capacity of NATO. Furthermore, I would argue that the USSR also had a saner economy than Germany in 1930-1940s.

Maybe if you had watched the video you would have seen the sources cited

I have gone through the slides, looked into the description. I did not find any relevant sources. Can you provide the timestamps and/or write the sources down?
So far, it does not seem like the claim that the US is in a significantly worse position than Germany was in 1930-1940s has any studies to support it.

Bizzare requirement

When did it become a bizarre requirement for claims to be sourced and for those sources to actually provide evidence for said claims?

EDIT:
Furthermore, I do not see how you can look at the US be able to dictate most of the world - including the rest of the imperial core - what to do, including blockade and invade countries that try to defy the US, and claim that Germany was in a stronger position in 1930-1940s when it did not have anywhere near the same capabilities.