It's only important that my character has enough competence to be likable and/or justify their role in the story I'm trying to tell with them. Beyond that, their competence is purely subject to how I want them to be perceived in relation to the world around them.
Ruben Sancho (My 'Pokemon Spear' character) had to be good at football because otherwise his avoidance of responsibility with managing his injury wouldn't be as meaningful. No one would care. He had to hold lots of status, otherwise his mismanagement of interpersonal relationships would look like pitiable incompetence rather than a lack of desire to take responsibility when the situation demanded it. What made Ruben and Pia work from a narrative standpoint was Pia's desire for control (As mentioned by Sapphy in the above comment) and Ruben's desire to stay as far from responsibility as possible but conflict would arrise when the life Ruben had built for himself (his football career) was an unavoidable influence on the relationship and he refused to take responsibility for that. In contrast to all of that, he had to be bad with Pokémon because his lack of inability to take responsibility and prioritise needed to be highlighted rather than it just being a case of "pokemon training is hard". Of course, being good with pokemon was the core metric everyone was measured by because the plot was a pokemon journey. TL;DR They needed to be good at something relevant to be worth following the journey of but it doesn't have to be the thing that is the central value system of the plot.
Lars Berrardi (My 'As the Dust Settles' Character) had a huge ego, so he had to be strong in order to reinforce that. Power scaling in RPs can be a challenge because people don't usually want their characters to be shown to be definitively weaker than anyone else's unless their character is specifically on a trajectory where they start off weak. Thankfully in that scenario I had a character who the headmaster of the school picked out as being above everyone else at my disposal, so I could use that to show my character being strong in a loss and even setting his personal journey into motion.
Between those two I've played plenty of character with varying degrees of competence, the likes of Logan and Jared are fun because I can be a bit more inconsistent with their competence due to their flaws being their respective desperate and anxious attachment styles. They're the types of characters that can be highly competent when being nurtured but crumble when forced to act independently, particularly when the opposition is the very people they want to be nurtured by.
D&D is a little different in that respect because as much as I want Luther Bastione to be highly competent but just short of those he sees himself as inferior to at any given moment, the dice decides on that one. His 'sword that will never rust' quickly became the 'sword that will never hit' and it's difficult to make a character look competent in that scenario. Thankfully in Khairo I again have a character, like Logan and Jared, whose competence under pressure can easily be put down to how secure he feels and becomes a character moment rather than just a poor dice roll.