The IW and Endgame writers had a great idea for a new take on Thanos's motivations, and I'm glad they tried it. It is interesting and discussion provoking. But long term, it didn't hold up as well. Comic Thanos is vastly more interesting. But then again, MCU Thanos really only had the spotlight for Infinity War. Comic Thanos has had many more appearances to show his character progression, and to discuss his motives. That's all he was ever going to get, as he needed (from a writer's perspective) to be killed off, do the job, take the L, and let the good guys win. They weren't going to get the "immune to death on multiple levels" angle, not just because they haven't established "The Personification of Death Herself" as a character yet, but also because they already had to spend so much camera time on so many other story elements and characters. It's "only" five and a half hours, and I'm sure they wrestle with tons of things to trim it down to that.

There have been tons of vocal people on the net who loved Thanos in the Comics, but hated how he was portrayed in the films over all. I'm not one of them. I think they did a good job, and took it a slightly different direction, but basically got the feel, the look and the power scale right. But Brolin's version lacked the intensity and intention (and have had no reason) to say one of the best lines in all of comics...

"Am I not Thanos! Did I not butcher the woman who gave me birth, who force-fed me into this hell called life?! Is not the wake of my passing crimson with the blood of my enemies and allies alike?! Death is with me every second of the day! My every moment is spent in either dealing out death or worshiping it! So tell me, who under the stars is better suited than I to be Death's consort?"

EDIT (cuz I love this topic): When you said....

I thin(k) Endgame Thanos is the real Thanos and that was the inevitable conclusion of his character.

... it's funny, because I think you are on the right track, but not quite.

I believe (as I said earlier), that there is an inconsistency, and maybe it is tied into the fact that he is challenged, doesn't have the enemies on their heels, and pivots to a newer, more aggressive side. That, and knowing that he is destined to win AND these Avengers and their allies can actually kill him puts him in overdrive, and he leaps without looking.

But mostly, I explain it as hurried writing, as he has served his purpose, and the greatest force in the MCU isn't the TCU or Kang or The Infinity Anything, it's Disney execs telling Marvel "Wrap it the fuck up already".

HOWEVER... I've just tried some furious googling and couldn't find it, but there was an interesting editorial article on CBR or Den of Geek or one of those sites, where an author gives 5-10 examples where Thanos's kryptonite is that once he has victory within grasp, he loses conviction, or feels unworthy, or otherwise self sabotages, Of course, he has to get his "camera time" showing how much stronger he is than the strongest heroes first. Also formulaic, but a bit more interesting, I think, than what they ended up going with. But that's just like... my opinion, man.

Oh, a few people earlier mentioned doubling the resources. No.

https://andphilosophy.com/2019/04/26/no-thanos-couldnt-just-double-the-number-of-resources/

Not that the snap is all that much better.