The border vertices are spaced out very uneven, see upper corners left and right for example? I assume with your mesh the verticed are distributed evenly, so you might want to do same for their UVs.
I mean not everything needs to be straightened, just where it makes sense, tube-like parts are easy case for example. Essential part of the equation is also how seams are set. When unwrapping organic topology, I sometimes straighten the borders, then relax the contained UVs. I would prioritise making progress in the…
Hmm. I see. I did think that the geo itself was going to be a contributing factor. That last example I posted were of the teeth and the edges aren’t exactly straight for it. The whole silhouette is ‘wavy’. Sooo… are you saying straightened UVs should primarily be used if patterns/details are needed in the texture…? But…