Neither juubi nor the jinchuuriki has been killed by senjutsu attacks. The only thing that came close to killing a juubi jinchuuriki was taijutsu of MIght Gai. Juubi has far better durability showing than its jinchuuriki (Even Sakura managed to hurt Kaguya). Juubi is vulnerable to senjutsu attacks but it can't be taken down permanently without sealing jutsu. It's regeneration is almost instant.
It's pointless to say that the juubi has never been killed by senjutsu attacks when none were used against it. And its jinchurikis weren't killed by senjutsu attacks because after the first time, its jinchurikis were able to guard against it better. Juubito/Juudara =/= Juubi. Kaguya has shown less vulnerability towards Senjutsu as she tanked 9 Bijuu-FRS going off at her at once without a scratch.
The Juubi is not more durable than its jinchurikis who are people with the Juubi's power compressed into humanoid form. Juubito was able to no-sell an Enton-Bijuu Mode FRS to the chest better than the Juubi taking the same thing, which burned it and inflicted noticeable pain.
The Juubi is going to take an extensive amount of time regenerating given its massive size. Naruto who's able to charge and throw his FRS very quickly can reduce it to paste. The Juubi's regeneration isn't so great that it can pull itself together when its molten pieces are scattered all across the battlefield.
Senjutsu can hurt not kill.
I find it hard to believe that while good old-fashioned Taijutsu is capable of killing juubi jinchurikis given sufficient power, that Senjutsu, the natural weakness of Juubi jins, is not capable of doing the same thing to the juubi itself once it damages enough of its body.
Why Juubi has better durability showing than the jinchuuriki? It's because Obito got hurt by a normal sized senjutsu enhanced rasengan. Madara got slashed by Sasuke and stabbed by Zetsu which killed him. Then Kaguya got thrashed by Sakura's punch and Kakashi's Kamui raikiri. Juubi doesn't have these inconsistent showings.
Those aren't "inconsistent showings". First off, you're comparing Senjutsu attacks that have been stated to be effective against the Juubijins regardless of durability with attacks that have no Senjutsu in them. You can't draw any cross-directional conclusions from them. All of those cases involve Sage/Rikudou/Kaguya's chakra which their bodies would be fragile to. The only case you have is Sakura punching a horn off, of which the durability is unknown, and only complements Sakura's punching power rather than downplaying Kagura's durability.
Juubi jinchuuriki are said to be stronger but they have poorer DC and durability showing than it's jinchuuriki.
Not true, given that that Juubito can produce more of the same TBBs that the Juubi can fire, and Kaguya who has a planet-level Gudoudama in her hands. And I already disproved the durability one up above - this time using how the Juubi and Juubito fared against the same exact attack with no senjutsu involved rather than comparing attacks of two significantly different natures used agaisnt them.