Well, I don't like this whole thing of "alphas" and "betas" but anyway. I wouldn't want to read about the OP hardcore "alpha" character who is perfect in every way. They get to f*ck all the girls and get all the riches. No struggle at all. Plus they make him a know-it-all who is always a step ahead of his enemies. Seems boring. Why would you want to read that?
The alternative seems more interesting, even if you don't like this "beta" MC. As many other people already said, he can only go up, right? Besides, the culture in Japan is completely different from us in the West, they do things differently and they don't see being overly "nice" as a bad thing as we do, but as a virtue. They also have deeply ingrained the destiny/reincarnation thing, so tropes like "childhood friends" or fated meetings that are meh for us are a huge thing for them. In their culture, being "alpha" is wrong. Just think about it, the stereotypical "alphas" "chads" "winners" and "f*ckboys" that people not so secretly fantasize to be here in the West are also the stereotypical Japanese delinquent, the kind of guy you constantly see Japanese MCs saving girls from.
Japanese have a duty to their society, and unlike here in the West, being hardworking and respectful is rewarded by women. Japanese women are constant victims of slut-shaming so it's only natural for them to marry at an early age. They don't even care about money as we do, is not uncommon for men to "marry up". Being a "simp" is not frowned upon either as being a dedicated partner is a virtue for Japanese society. Why there is an abundance of "betas" and "simp" characters in anime, manga, and Light novels? Simple. Because Japanse like that stuff and BUY that stuff.
But what do I know, anyway? I'm just a dinosaur.