Burden sharing has been a problem for some time. Things were getting better, but CV19 has put everything back by some considerable margin. I am often struck how some of the smaller NATO Nations take their collective responsibilities far more seriously than certain large (freeloading) Nations. These smaller nations are not always the ones with the obvious motivation.The US has still maintained a sizeable and expensive military, that is expected to intervene on behalf of NATO. But an increasing burden is being placed on the US by its partners overseas, who are more worried about their collective welfare states then making necessary contributions to an alliance. With one in particular providing the necessary hard cash to help modernize the Russians military.
Then when you have other issues like China, Iran, Climate Change etc. Where National interests collide and take precedence over being mates. If we can’t work with each other, we will work against each other raising tensions further.