https://foxglove.dev/homepage
imho foxglove is the way to go for ros2 robot visualization.
A few weeks ago I was porting my virtual robot model back to urdf and noticed that the robot was showing up in foxglove in white instead of the defined colors.
I doublechecked the tutorial and confirmed that I was doing it correctly
(And I remembered something similar happening years ago in rviz with multiple geometry items in a single link. The tldr; was that if you had more than one geometry item in a link the material/color information was ignored. seems that rviz2 and foxglove behaved the same way. weird.)
So I started a topic on their discord and was amazed that within the next few weeks they pushed a codefix to their web app and their apps.
So... If you're visualizing a robot in with multiple geometry features per link you'll get a better result in foxglove than rviz2 now. :-)