The USA's ability to restrict China depends on its abilities to forge effective alliances with Far Eastern countries. Trump might be superficially bellicose, but his unpredicability, uneven foreign policy and "America First" attitude actually diminishes this. The Trump administration has surely put China first and foremost as an opponent, but what is the point of that if the president also undermines what needs to be done to oppose it?It's unclear Biden's position on China, and Trump likely will back countries attacked by China like he backed India with a carrier strike group when China attacked India and sent ships down the Taiwan Straits when China sent planes towards it.
This is not true. In fact, most of these countries are increasing defence spending - albeit from very low levels (~1%) in some cases.And the reason that Trump wants to scare allies is so they could increase military spending even this Vox video admitted that many allies like Japan, Germany, and etc are lowering defense spending
Also, the EU and NATO are not really relevant to China. The EU is too far away to meaningfully get involved militarily bar very minor support. I think there is some general agreement in the EU that they need to increase defence spending (those below 2% GDP have generally agreed to increase to 2%, albeit gradually), but it will focused around Africa and Russia. The primary responsibility for defence of the Far East is the nations there. There are other allies: India, rapidly growing into a significant power, will surely oppose Chinese influence along the Indian Ocean, Myanmar to Indonesia.
???now they could bandwagon with China/Russia, but China already tried it, and failed, and Russia already tried to join the EU, and it failed.
Russia has never attempted to join the EU - or do you mean it tried to so the same thing as the EU, in which case can you clarify what?