I don't know if you still need help, but maybe someone might find this useful. I struggled with getting in the boot menu too, but eventually found a solution that worked:
2. Press and hold volume up button until the phone turns on and android logo and text "no command" shows up
3. Simultaneously press volume up and power button (this took a few tries)
4. Boot menu should appear now
With OREO, none of these methods seem to be working.
Power with Vol+, no
Power with Vol-, no
Both of these tried with and without cable connected to charger and PC.
What is the Factory reset method that is working?
Safe Mode is possible with Power and Vol-
OK, managed to find the way.