I upgraded from 4.2.15 to 4.3.47 to test this out, and graph visualization now works for me (older versions of 4.3 did not work). I’m using 2021.2.9f1 and URP 12.1.4. I tested out both the 2D Renderer and Forward Renderer, and both were able to display grid graphs in the scene view, and also in the game view.
Unrelated to graph visualization, but here’s a note about upgrading to 4.3.47 from older versions: There are now a number of asmdef files, so if your project is using asmdefs then you’ll not only need to add the core Astar asmdef (AstarPathfindingProject.asmdef), but possibly a couple others. I needed to add Drawing/ALINE.asmdef, and PackageTools/PackageTools.asmdef.