Looking for a novel where MC is born or transported to a magical or sci-fi world and got himself some powerful treasure/talent/system, but after deciding to conceal his growth speed he actually successfully achieves it at least until he is too powerful to continue hiding.
You can read anything that has "sign in" in it's title, something like : 80 Years Of Signing-In At The Cold Palace, I Am Unrivalled Hide in the Banished Palace and Level Up To A Big Boss Sign In: Becoming A Great Spell Deity Starting From The Magic Academy Xianxia: My Disciples are Insane!