Just bumping this in hopes someone will see it:
https://kotlinlang.slack.com/archives/CJLTWPH7S/p1743431929029219
Basically, it looks like the only background available for bottom sheets is a solid color. I would have expected a painter to be avaiable, but there doesn't seem to be one.
I did figure out a workaround, but i have to send in a null drag handle, and render one myself as part of the content, which also means having to play with the semantics to get the dismiss action registered on the drag handle.