With the Stick which is model XPL3100, you can turn it off today, but you can not turn it back on without taking the power out from back of stick and placing it back.
Since there is no IR sensor it is impossible to turn the XPL3100 back on Via remote, from total shut down.
There is a way for you to try to shut down if you have a 2018 or 2019 TV, under settings on your Box turn on CEC that way, you connect your XPL3100 Power to TV USB. and when you turn off your TV your box shuts down too. and When you turn on TV your XPL3100 turns back on.