Yeah, flat cutting the population, or increasing the resource size, was silly. At a modest 1% growth rate, a large population will double in about 70 years - if you cut the population in half, that's undone in less than a century. If you double the available resources, the population will double to meet that in a century.
If you cap the growth rate very low, you leave the population unable to recover from catastrophe.
What he should have done is snap a lick of dang sense into the population of the Universe. Probably ending the suffering caused by war and greed and bigotry in the process.
In the MCU, he wasn't the "Mad Titan". He was the Dumb@ss Titan. They would have been better off if they'd left his comics motivation - literally courting Death - intact. It isn't any smarter, but at least it doesn't pretend to be rational then.