Although the CM0 cannot be purchased outside of China, an SBC based on the CM0,CM0 NANO is published by EDATEC.
Both DigiKey and Mouser have it in stock.
Actually, a point that many, including myself have missed is that the CM0 actually supports Bluetooth 5.0 compared to the Zero 2W's Bluetooth 4.2. According to the datasheet provided by Raspberry Pi, it uses a Cypress CYW43439 instead of a Synaptics SYN43436, which the only difference is the difference in bluetooth version.