@Mariano I run all homebrew campaigns so no one's going to know what I'm necessarily planning next, but I do have one friend in my online group who definitely cheats his butt off when it comes to to hit rolls and ability checks. He's a part time coder and he uses a dice roller on his PC that I'm sure is loaded with bs numbers in his favor. Everyone else rolls dice on camera, but oh no... And yes, everyone knows about it. It's like an open secret.
While he can have some main character syndrome going on, he's mainly just a power gamer. And at my experience at running these things, I know how to temper things discreetly if he leans too close to trying to one up other players.
So why do I put up with it?
For all his tough bravado in and out of game, he's had a hard life. He hides a severe anxiety problem by over compensating. Psychologically, the guy has a lot going on, from internal and external forces. I'm not ignorant of this.
Generally speaking, as long as he doesn't cross the line of making the game unfun for others (and again, we know him pretty well), I'm okay if he wants to play something bigger than himself. Someone powerful, charming, cool, etc. He can roleplay reasonably well and he doesn't need to be perfect. But he needs a friend or even several. That's my group. We've known him for decades.
When we get older, social quirks and dubious decisions that you might make regularly when you're younger become less charming and excusable. And older guys especially have trouble making new friends as men have families, which is often less time for hobbies and our peers potentially grow more aloof.
There's been some dangerous unstable people out there where he lives in the last few years that started getting his attention. Making him feel big in all the wrong ways. You can imagine who they are. But if the rest of us, his old friends, can remind him of who he is and that he has a place with us like he always did, then yes... I will look the other way a little for the game and for him.
I don't respect cheating at all. But if I can do this one little thing that might make his weekend and ease the fault lines in his soul, then I'll cop to having this motivation for the greater good. I always want to be a good a good gamemaster, but there's more to the gaming table than rules and rolling dice once you do it enough.
I apologize for the long answer that might be off the rails for a response, but I wanted to offer my own perspective on this.