opacity map painter
Same cursor system as geometry editor or mesh grabber, provide means to paint opacity maps directly in viewport to generate the map file for the surface currently being worked on.
Brush size and softness would do, brush shapes would be aces.

Comments
I think you could do this with the map painting in the Strand Based Hair Editor. You could paint a density map and put it in the opacity channel. I haven't tried exactly this, but I have used the maps in other ways.
its funny they purchased garibaldi with a multi UDIM map painter and kept it hidden in the SBH Editor.
I havent installed the new daz 2025 to see what SBH is like there, maybe it is more accessible instead of hidden in SBH editor.