Devil's advocate: no action short of landing your own project will prove that you use a library. I've donated to stuff like Godot (which I have yet to open myself) and Blender (which I only know the bare basics of; I haven't even tried the new UI overhaul) years back because they are projects I appreciate an open source alternative for these very complex problems.

of course, giving cash is a much bigger gesture than just pressing a star button, but it sounds like the star button is closer in vein to the kinds of acknowledgement people are asking for here.