Firstly let me say there is magical resistance, magical defence and physical defence compiled here. What is consistent is her physical defence, from getting hurt by Kazuma to actually bleeding from his dagger and even scaldded her hand from very hot water.
Magic resistance:
Aqua magic resistance:
["Ara. So Kazuma, you think you're the strongest one here? Your skills might be convenient and can take down people like Darkness easily with Drain Touch… But have you forgotten? A lich skill like Drain Touch will only work if I'm not paying attention. Do you really think you can do anything to me?"] - Volume 9 Chapter 2
["Hey, the one that proclaims to be a something, get over here."
I dragged that woman who was loudly blurting out her schemes over. I felt that she had the most mana among all of us.
"Hey, what are you doing?! I don't have time for you Kazuma. Let's just, hyaaa―!?"
Aqua couldn't resist my sudden Drain Touch and shrieked.
"You hikiNEET, what are you doing to me during an emergency!?"] - Volume 2 Chapter 5
Physical defence:
[After purifying the hot spring, Aqua cast healing magic on her scalded hand. That energetic idiot looked really depressed right now.
Seeing her like this made me feel uneasy too…] - Volume 4 Chapter 5
[I wordlessly shoved the tip of my dagger into her hand.
"…! …!"
Aqua recoiled, covering the wound with her hand, barely making a sound due to the pain.] - Volume 14 Chapter 5
[As she removed her hand, Aqua's wound was still bleeding without any sign of being healed at all.] - Volume 14 Chapter 5
Also Wiz never fought on equal with Vanir with her own power, she even brough other scrolls and other stuff, especially this:
[ Moi had seen that crystal before.
It was a forbidden fruit that would consume the user's lifespan in exchange for an extreme amount of magic power…
At the same time that Moi had affirmed the identity of the crystal――
Announcing the beginning of our true battle, Wiz shouted with extraordinary spirit.
"'Inferno'――!"] - Masked Spinoff
Also in that very story:
["Why are you such an unfair devil…? I used that many manatite and scrolls, and went so far as to use a forbidden item… Is there even a way to defeat you?"
"If thy want to at least deplete one of Moi lives, I suppose thy shall need to learn explosion magic."] - Masked Spinoff
Then let's go back to volume 3:
"What are you saying? Even moi didn't make it out unscathed after taking such a grand attack. Look closely at this mask."
He pointed to the forehead of his mask.
Looking at it carefully, a 'II' was written on it.
"Because of the explosion spell, I lost a life. I'm Vanir MK II now."] - Volume 3 Epilogue
Then let's go towards volume 9:
["Didn't you lose to Wiz when we fought the Destroyer?"
"That's history now. Since I've leveled up, I learned all sorts of skills related to increasing the power of explosion magic. Wiz and I compared the power of our explosion spells some time ago and won. I am the number one in Axel right now."] - Volume 9 Chapter 4
Conclusion:
Wiz can freeze an area the size Kazuma's < mansion if she went all out. Pure destructive power she loses to Megumin. After she became a lich she was able to cut the demon king's barrier maintained by 4 demon generals (don't ask me how it's 'maintained', even I wouldn't be mad enough to employ melee fighters and a slime to maintain a magical barrier). She then proceeded to defeat, the demon king generals, Hans, Sylvia and Beldia, all of whom would be one shotted by Megumin, also:
["About that, Sylvia-sama was unaffected by the magic, but then for some reason the invader charged forward. When Sylvia-sama's body was touched, she suddenly collapsed and has become unable to fight, just like Hans-sama…!"] - Masked Spinoff
Even after that power gain she wasn't effective against Sylvia who was one shotted by Kazuma's group using a gun that condensed magic power, I should also add this:
[Without question, it was the best Explosion I've seen so far.
Along with the deafening roar, a wind blast that was bigger than I imagined blew toward me.
If she had unleashed this on Sylvia, she might've just defeated her without relying on that weapon. That was how powerful it was.] - Volume 5 Chapter 6
Also the part about wiz resisting [Turn Undead]
["You're acting too arrogant for a lich! An Archpriest like me will perform such benevolent acts, so just scram! You're taking too much time, watch me purify the whole cemetery along with you!"
"Eh? Wait, stop!"
The lich started to panic when she heard Aqua's words.
But Aqua ignored her, opened her arms and shouted:
"Turn Undead―!"
A white light encompassed the entire cemetery with Aqua in the middle.
The light seemed to be gushing out from Aqua's body, and caused the zombies around the lich to vanish upon contact.
It was the same with the spirits gathering at the magic circle of the lich, they disappeared when Aqua's light reached them. The lich was also basked in that light…
"Hya―! My, my body's fading! Stop, my body's disappearing! I'll be purified!"
"Ha, foolish lich! Your existence goes against the law of nature, an undead which defies the will of the gods! Disappear, be vanquished by my power!"] Volume 1 Chapter 2
Also the tiers will get recalculated, it's going great? CRT is largely being ignored, once i've compiled that is. Also you're speaking of tiers, do you not see at what stage CRT is at? Also resistance and immunity is different, Aqua hasn't yet bypassed immunities since the number one term is 'resistance' in Konosuba, but she bypassed resistance to holy or more like her magic was powerful enough but did less damage than it should do to the resistance and I've already stated who (Beldia).