Waking Mac mini from computer or iPad?

So I recently purchased a Luna Display to run my Mac Mini headless as an audio player connected to my stereo. I have sleep and the login screen turned off, but I can’t wake the mini up when I use a secondary computer or iPad without using a mouse connected to the mini. Is there some sort of magical setting that should be used?

Not sure if it is the same but I have Astropad Studio and I wake my imac up by by bring up the keyboard on astropad connection and hitting the space bar. Hope this is of some help.