>>unless they think the current world order, the “Pax Americana” is in play
If by "Pax Americana" you mean the current global system of international trade with US-provided blue water overwatch (at its own expense) and access to US markets - all initiated by the Bretton Woods accords, then, yeah, the US has been moving away from that for the last three or four presidential administrations.
Bretton Woods was, essentially, a bribe to keep nations out of the Soviet orbit. Nixon invited China in as a move to break up the Sov-China alliance. It worked. It also lifted many people in China from abject poverty and the availability of that inexpensive labor pool plus cheap enough blue water transport extended the post-WWII "long boom". No idea if either of those were the intended result but using it to break an alliance has 'Kissinger' all over it - as does a president having domestic troubles (Watergate) looking for an accomplishment overseas.
There's been less reason for Bretton Woods since the USSR collapsed (although, arguably, that's still something in process) but the US was stuck maintaining it as it was reliant on Persian Gulf energy - something no longer the case. Xi is not wrong in seeing the global situation changing, and China is a net importer of energy and food.
All that said, there were signs that dynamic zero Covid was failing to contain Omicron. I'd expect that Xi saw a way to use the white paper protests to deflect blame and maintain CCP primacy. Plus, of course protests were of concern, geographically widespread ones that included multiple classes even more so. If nothing else those protests looked to be mass super-spreader events, and it was just a matter of time before it became obvious that dynamic zero covid was no longer working. For Xi, it was a matter of two problems together providing their own solution.
To be fair, zero-Covid did save millions of lives. If only they'd used the time it provided to push vaccination. Yes, there was vaccine hesitancy, but making it a factor keeping the Covid app on yellow rather than turning green after a non-positive test might have been enough.
Just my $0.02...
