many times I found myself not able to fully use the proportional edit as it was not exactly what you want or need, it gets you close but I think with the option of editing the falloff you can create so much more complex and interesting curves on the mesh.
let me know your thoughts and maybe we can get this feature into blender at one point!
About the proportional editing it worth at least to have an invert curve option. It is frustrating when it goes the way you don’t want.
Like that for instance:
I see what you mean and agree that we need a way to modifiy it.
I think it the fastest way would be to just copy the custom falloff curve option from the sculpt workspace. It’s powerful but also simple enough to quickly invert curves. But a button in this menu to invert the shape along the diagonal could be a nice addition.
In case of specific need. The Sharp curve is sort of an inverted profile to the one you are demonstrating here. And the proportional editing size can be used to tweak the sharpness here.
Having just the inverted sharp doesn’t solve the problem, better to have an inverted button to use say the sphere but in the opposite direction. Custom profiles could help also