I honestly don't understand. I play the game to play it, and acting "in character" or setting limits on myself seems boring and unnecessary. Do you roleplay, and if you do, can you explain the appeal of it?
Conceive of who the player character is...many times. The player character is a different person, every time I play, with different skills, because it has a different personality. Don't attempt to play a character that would do the things that make them so powerful that you feel no challenge.
If you want a challenge, then challenge yourself. Build a weak character and don't do the things that make you, in your subjective opinion, "over-powered". Make up a personality that WOULDN'T do those things. Doesn't want to, or can't. The point of the "role-playing" part of "role-playing game" is too be creative. Some players don't understand this, or can't understand this.
The game is the tool used to create your character (hammer & chisel or paint brush), and the skills and abilities are the material from which the object is created (the clay, stone or paint). In this case...a player character.
If that seems unbearably pretentious, please understand that "pretense" is the entire reason the game exists. It is w
hat you are supposed to be doing! Pretending.
Anything that displays "pretense" is "pretentious". That's how the language works. To "pretend" is inherently "pretentious". Literally.
Reading this back (after I posted...sigh) l seems condescending and acid. Sorry. It welled up as a reply many, many different posts I've read. But you asked an honest question, I apologize.
Though, if you can ignore the condescension (please), it does explain the question you asked.