Hello, i have the same issue ith a Pixel 7a.
After the manual installation with flash-all.bat , the phone always boot in fastoot mode.
Even after “clicking” Start button.
The device is recognized with fastboot console :
fastboot devices
392XXXXXX fastboot
How can I restart the phone ?
EDIT : Having an anwser here Pixel 7a black screen of death - #10 by Jeantoine