Odo doing his best impression of an innocent cat

I think Odo self limited his abilities in order to placate the solids. Like playing a game on hardcore difficulty while also self-imposing only starter weapons and no legendary armor. That's why he was always so exasperated. He tried to make the game harder but the game was still too easy. Like a true nerd it turned out the ultimate challenge was interpersonal relationships, and the s-level challenge was keeping his girlfriend happy