I want
IF
it is 4pm, (or when some event happens)
THEN
Turn Light switch ON
Wait 10 min
Turn same Light switch OFF
Wait 5 min turn same switch ON
Wait 10 min
Turn same Light switch OFF
END
This type of routine is the one that Alexa does well, for all its deficiencies. I personally in my setup would run the first instance local in ST and then use a virtual switch to pass to Alexa, probably with a notification included.
You could also just start with the virtual switch in ST and have the ST Routine do the “every day at 4pm, turn on virtual switch” which could then be used by Alexa to turn on/off the physical device and then turn off the virtual switch as the last step.
Exactly. I was thinking in terms of maybe with the first triggering running another action e.g. switching on another light, but true, would be simpler as you say.
Sure. There are many options as we know. It will really depend on what the OP really wants the true flow to be vs the example provided.