[Edit] I am having trouble getting a stock image of Raspberry Pi OS to boot on a Zero W. Using Raspberry Pi Imager 1.7 to flash the image onto a 32GB Sandisk SD card from a Mac M1.
After inserting the SD card back into the Pi and connecting an official power source, the Pi ACT light flashes in a strange pattern. When HDMI is connected, the display is black except for a faint, slow, regular flicker. I checked the LED Warning Flash Codes page but am still not sure what I'm seeing, it looks like "long-short-long" which is not listed.
If it is a partition issue, please let me know what I should do differently during the flashing stage. I have tried multiple different SD cards, and reformatting using the official SD card software as well as the RPi Imager "Erase" option.