No, it won't cede worldwide leadership to China.

The Chinese government is a dictatorship which runs a "China-first" economic policy with a weak legal system and intellectual property laws designed to benefit China.  The Chinese government is unpopular in Asia, and while Europe's leaders make a big show of negotiating with China's leaders, the European governments don't fully trust Chinese leadership and can't afford to fully trust them.

No, nothings going to change as result of Trump's decision as far as China is concerned.  Today Trump put America back in the leader's seat on the climate issue.  Once again, brilliant 6D chess from Trump and his team.