You're literally lying.
It shows us Walters prepping for her closing arguments, and nervous about pulling it off. And that's from after the Hulking, before we go back to see how she became a Hulk.
She doesn't "master being a Hulk". She has enough control to turn it on and off. Which isn't hard for anyone but Bruce, because the problems Bruce has are down to his dissociative identity disorder, which has nothing to do with the gamma radiation. There's nothing to "master". They explain this in detail repeatedly, and you're intentionally ignoring that to push your agenda.
She and Bruce don't have a real fight. They're family, and they're tousling. It's friendly. Neither of them "wins" that fight, they eventually roll into and destroy the bar and they both quit.
Yeah, she beats Titania in a single punch in their first encounter, because that was setup. She's the main villain of the series. It's not gonna be that easy in Round 2.
It was a prologue infodump. Why you're expecting significant adversity from it is baffling. That doesn't make a character "unrelatable" or "boring".That is just bad writing. If everything comes so easy to the Main Characters then she is very unrelatable and boring.
She-Hulk is no way "unbeatable" and you literally don't have grounds to make that claim. Nor have they even started to explore her weak points. All you're really saying is that you're upset that there's a strong, competent female character, who can hold her own next to a male character.If they want to make her unbeatable then they need to give her other weaknesses. Like the mentioned Saitama. A character that is unbeatable, successful, attractive and smart is just extremely bland.
Especially after the infodump prologue which only serves to explain how she became a Hulk and how much of Bruce's Hulk problems are unique to Bruce.
A female character didn't royally screw something up or fail in some significant way in a single episode, and that's where you decide to call her a "Mary Sue". That's misogyny, and a misuse of the term.