to continue a thought from another thread since it crosses into *SPOILER* discussion
I think part of Thanos' plan has to deal with the population at large taking for granted the opportunity they have at life to be more than the ungrateful consumers of all resources around the universe.
To kill off half the universe should make the other half feel grateful to have survived, and then thrive as a species to be better than what they once were.
That is something that doesn't get solved by simply doubling the resources of the universe, as that allows the already ungrateful population to just double up on consumption and continue the current destructive ways without consequence.
To speak any further requires spoiler tags, and that's too much work from my phone. But you kinda mentioned it in your post above.
Where Thanos thought that life itself should owe him thanks and gratitude's for giving them the space to thrive and be better, instead of continually being congested and stepping on each other to get ahead. His visit to the future to see his plan executed before he actually had to execute it, revealed something to him...
In Endgame, Thanos realized the error of his ways, in that he left the other half who would remember those that were gone, and instead of being thankful that they survived, they mourned those that they lost and had trouble doing much more than trying to find their way back to a normal center. Cutting the population in half was only addressing the issue he sought to fix at the surface.
His revised solution was to end all life and recreate it in his image, so that they could thrive as species and be better than what once was before, now that they had no memory of the past and therefore did not long to regain what was lost, but instead only saw what could be moving forward.
So while I agree his initial plan was flawed, I also think in his mind it made sense at the time.
and seeing how he saw the flaw in his own plan after seeing it executed... and then undone, you learn the underlying reason for him wanting to "fix" said problem in the first place.
But I've only seen the movie once (so far) so I may have some extrapolation of details in my mind that weren't in the movie. It's been in there marinating for a few days now.