Yuji takes a few attacks from ISB Mahito who's
3x stronger than him
The profile is inaccurate. It was decided that ISB is only a 2x increase because the Japanese translation says he's at 200% of his normal power. And surviving a couple hits from someone twice as strong as you is feasible for any person. It would hurt like a *****, yeah, but it's survivable. Especially when you consider Yuji's pain tolerance.
Okay, but I don't think Yuji is going all out on a dude he just wants to request the help from. They weren't having an all out-fight. Not to mention most of Yuji's strength comes from his body, with only a small fraction of it coming from Cursed Energy reinforcement (As stated by Nanami). So most people wouldn't be able to accurately gauge his strength either.
Kenjaku who's freaking KENJAKU was
impressed at how tough Yuji was.
Fair, but there's also people being surprised/shocked/scared or taking note of Yuji's strength as well (Todo, Nanami, Ino, etc.)
Yuji even implies
durability is his greatest strength, which is supplemented by Higuruma calling Yuji
an unbreakable doll.
He doesn't imply durability is his greatest strength. In fact, he implies he has several because he states "Yeah, that's
one thing I've got going for me." And I'm pretty sure in the same fight, Higuruma takes note of Yuji's monstrous strength.
Given
the CE flashing around Ryu, it probably involved CE discharge; when they were regularly trading blows
Yuta was fine.
He explicitly states in the page you sent that if he didn't block/redirect Ryu's blows carefully, that he would take damage. Him not blocking that elbow check was an example of him failing to guard properly.
That's only in the anime, where Toji doesn't even
make the statement about timing like he did in the manga. In the manga, I think the idea is that Toji got hit head on and thought the power of Red was monstrous, but if he doesn't mess up the timing, he can block future uses with ISOH. Heck, even Purple only obliterates Toji at the center of its impact, given that
the hole behind Toji is much bigger than the hole in his body.
I don't think the implication was that he took it head on at all. Especially since the Anime explicitly shows us he blocked it with ISoH. And the attack still knocked him on his ass, and forced him to check if his bones were broken from the impact. Red is clearly > Toji. And I don't even think you're supposed to think about the Purple that much, but if were are going to make some conclusion about that, it should be that Purple started small, and grew larger as it passed through Toji (It started as a small "sparkle" in Gojo's hand, and obviously grew to that size to leave behind that sort of damage). Which is consistent since Purple grows as it's fully formed and launched (And Gojo's first Purple looked differently from every other case at that, so it's an extra special case).
But also yeah... a normal wall is obviously less durable than Toji. In case my comment seemed to imply Toji = Wall level which it wasn't. Obviously the far less durable wall is going to take more damage than Toji does.