Thank you so much again for taking the time to test this out and for your detailed reply! As you can see, this does indeed cause some errors in the genital area. I’m not sure if it’s an issue with the morphs themselves or an inherent problem with the VaM character's genital mesh, which tends to act up during slightly exaggerated bends—especially on thinner characters.
I haven't been able to find a better morph that can simultaneously adjust both the body and genital sizes without causing errors, mostly because a lot of characters are just too large for my preference. That said, your advice was incredibly helpful. Even though there might still be some internal mesh errors, it looks much better now at least.