Since you can program the Harmony remote to emulate any other IR remote, whatever you can do with your original remote will also work with it - simply “learn” the Power ON command from your original. 
Working Perfectly on my H96 Max X2 (S905X2)
Just had to tell Harmony no power buttons
No long press on OK for menu BUT Menu button does the same 
I set one up for a friend. Found Beelink in Logitech. It came up when entered.
I ended up leaving it on all the time since it draws so little power.