Profile0: Normal Mode, i spent hours to get all collectibles.
But then i realised, much before final battle that the hours played was a little too much (around 13 hours), and i used the cheat "Low play time" to put the timer at 3 hours.
And I remembered that, one day I left the game on for more than 8 hours, and I forgot to put the Switch in Standby.
Aside from that, the game was finished in a Legit way.
Saved before final battle. And since the game was completed, Normal Mode Gallery Full Unlocked.
Profile1: Hard Mode, this is literally a Copy of Profile0 (after the final boss and credits, but save before final battle), with Difficulty changed to Hard-Mode.
Normal and Hard Mode Gallery Full Unlocked.