The command line install page Install /e/OS on a Google Pixel 5 - “redfin” says
Before following these instructions please ensure that the device is on the latest Android 14 firmware.
What OS is on your computer, if Windows the most frequent issue is that Windows has not installed a full driver set (ok for ordinary use but does not detect the phone in Fastboot mode) resulting in
Error on step: device-detection
Fixed like this [Solved] Windows does not see my phone in Fastboot mode.