How do I change things so there’s less arguing and attitudes

we have a 5yo son and we’re really struggling with his attitude and arguments. He’s highly intelligent, so most everything he says is rational or logical or a good response, and he’s really strongwilled, so he’s not learning to respect our decisions or boundaries, and he’s developing an attitude.

for eg I noticed he left a mess on the table after eating so I told him to clean it up, and he did it like half-way and started walking away so I told him there was a ”few more crumbs” and he goes back to the table to clean it up and says “it’s not a few, it’s a lot”.

thats one of the things he does, and tbh I find it infurating, because it’s like little nit picky shit and its not helpful or necessary.

so I ask him if he knew there was “a lot” on the table why he walked away before it was clean and he just points to the table and says “look I cleaned it”- pointing to the fact that he had now cleaned it

and this just goes on and on, him trying to excuse and justify and weasel his way out of everything in this conversation until I just finally let him go.

i hate that I’m getting into these situations with a child because im trying not to assume something malicious and he really may just not understand what im saying but ultimately he’s always talking back to me, and he just has such an attitude with me that i really find him hard to deal with and tolerate.

it’s frustrating because I feel like it mostly only happens when mom is around. when it’s just me and him, he listens, is respectful, does what hes supposed to, and we have a lot of fun together- it’s not always easy, of course, we have challenges, but it’s different when it’s the three of us- he immediately becomes argumentative, whiney, defiant, and pushes boundaries, and if I were to be honest I feel like his mom does give into him a lot of the times, he knows she’ll give in if he keeps pressing, whereas I don’t.

and what’s messed up is I think this is just who he is, because we don’t model this type of behavior, we don’t talk to each other or others this way, but he’s just different from us, and my everyone who knows him has told us how “wild“ or “difficult” he is, and he’s a good, sweet kid, but he’s so hard-headed, and even my wife and I have talked about it how we never knew anyone like this or grew up around anyone like him and if we did know people like him we wouldn’t want to be around him; and we’re stuck with him.

and I know a lot of people will say to just not argue with him, but it is not that easy, he tries to turn everything into an argument and even when we’re firm with our boundaries or shut down convos he persists. It’s just not very easy right now

im hoping this is a phase, im hoping he grows out of it but A. I feel responsible to show him how to be a good, stand-up person, and B. I don’t want to deal with this when he’s older you know, because if he’s going to be this way his entire life, he’s going to be a nightmare to be around.

I don’t know, I just need to figure out how to communicate better and make it clear that his attitude and behavior is not okay and it needs to change.

Any advice is appreciated.