The SE manual seems to agree with what I was told by the installers.Great. So we have three answers here.
The SE manual seems to say the opposite from the video. Shut down via the DC switch, wait for the ‘do not open’ warning to disappear, then turn off the AC switch/breaker.
AC on to power up the inverter circuits and then DC for the PV.
That makes sense to me. But my Tesla guy still never killed the AC breaker and I’m still wondering if the DC (inverter) switch kills everything on newer configurations.