ATX12VO is not implemented into the Z690 chipset based motherboards for Alder Lake. The manufacturers seem to have moved away from it. The standard requires a new compatible PSU with a 12V connector with 10 pins, the dc-dc conversion from 12 volts to the 5 and 3.3V for, for example, disks and fans would now take place on the motherboard. 

The new PSU standard offers increased efficiency and lower idle consumption. However, every motherboard manufacturer is required to make at least one model that can handle this new connector. In order to meet this requirement, a product does not have to be released, but it must be designed.

Currently the AsRock Z590 Phantom Gamin 4SR and the Z590 Pro 12VO that MSI showed off in a video are the only motherboards that support the 12 volts PSU. For Intel's approval, Seasonic has submitted its Focus GX 650W power supply. Perhaps We'll need to wait until the 12th generation Core desktop processors and motherboards, along with compatible power supplies, are released.

Intel Z690 motherboards remain to use 24 pin connector over ATX12VO