Total global warming is predicated on total CO2 emissions, which is the bottom line that is most significant. Yes, the US has higher per-capita emissions, and absolutely
should reduce those. However US emissions have been flat or declining for decades now (since the 1970s or 1980s depending on how you look at it), whilst China's emissions, both total and per capita, have exploded in the past four decades as that country has industrialised and emerged as a mid-income nation.
These facts re-hash arguments about planetary limits which have been ongoing since the 1970s if not before, and pit past growth, consumption, and pollution amongst western nations (the US, Europe, Canada, Japan, and Australia, largely), with the hopes for economic growth, still strongly coupled to consumption and emissions, of the rest of the world, quite notably China and India, but also Africa's future billion or so in coming decades. It's notable that despite the Industrial Revolution and carbon age being roughly 250 years old, half of all emissions date from the 1970s, a time at which Western emissions were slowing heavily following the 1970s oil shocks.
It's not a case of either/or but both, the reality is complex, and simple, and most especially nationalistic simplifications, finger-pointing, or whataboutisms really don't advance the discussion.
<https://ourworldindata.org/co2-emissions>