I am a newbie with my DJI Mini SE and could not get my controller to start up, even though it showed 4 lights charged.  I tried all the various fixes listed in the forum threads to no success.  Finally, this morning, I realized I was pressing the button on the left of the controller (return to home) and not the POWER button on the right.  Using the correct button, controller started up normally, duh!
Thought this might help others with this "perceived" problem.

Pressing the correct button does help, lol, I have done the same thing myself, occasionally, when distracted and I am not a newbie.

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