If you're just going to keep on infantalising mature adults and denying them acknowledgement of their adulthood, because you are mapping something onto them which they are not - if that's your stance and opinion, you can certainly hold it - but it's not relevant or productive to this thread. It's actually harmful, and it's not welcome here.
Enough; this train of discussion is going off the rails in a way we've been striving to avoid in this thread - we're talking about making the models look better; which is to say, to make the models look like healthy, natural, mature creatures that are comfortable in their own bodies. BG3 halflings do not look like this right now, and it creates a notable dissonance of experience. Other games avoid this dissonance in various other ways, usually by making models that are far more satisfying to appreciate as whole and complete, natural, healthy creatures, in and of their own.
If we want to be productive, but you don't like any of the suggestions made so far, or any of the comparisons, then let me ask you instead: How would you change the current models so that these 3-foot halflings look like healthy, natural creatures that might exist, that look mature for their species, and that can participate in intimate sequences to the same degree as their larger-sized counterparts? What would you suggest?