After following connects did Amber open automatically or what were your last steps switching between apps?
After testing and failing a bunch of times using the scan QR method, I did get it to work (with Vanadium/Amber/Graphene) by going the other way around.
Creating a generic nsec bunker inside Amber, then pasting that in vanadium did work.
https://video.nostr.build/211dcdfc4276b8327c7fb761f6b2be6e9d289ecbb4c98042c0e72dd4f4a4db1a.mp4
Discussion
Amber had a popup that opened when I clicked on it. I didn't cut out anything. At the end it automatically sent me back to vanadium.
Maybe one missing step not shown was going to the Amber app settings and "Force Stopping" it after each prior failed attempt to use the QR code.