deskthority

A lot of new keyboards coming out these days, especially from Chinese manufacturers, seem to all support USC-C wired with detachable cable, 2.4GHz wireless with 1000 Hz polling rate and Bluetooth connectivity for up to 3 devices. And they almost all run QMK+VIA.

Is there some new HID chip coming out of China that everyone is using on these keyboards?

I don't know what any of those keyboards are using, but my guess is that they could be newer models of ESP32 microcontrollers. They are inexpensive, widely available, popular and sourced from China, but it is only in the last couple of years that there have been ESP32 chips with USB PHY in addition to wireless.
Before that the most popular choice for keyboards with wirelesss+USB had been the Nordic nRF53840, but it couldn't be used with QMK because its bundled drivers had a license incompatible with the GPL.

Would the nRF53840 chip support ZMK? Im currently in the middle of a project using the nRF53840 and did not know about this issue.

Yes, ZMK supports the Nordic Semi chips. I think that is one of the driving-forces behind its adoption.