The 780m is an integrated GPU. I specified discrete GPUs because that's what I have tested and can confirm will work.

I have dozens of different AMD GPUs and I personally host most of the Debian ROCm Team's continuous integration servers. Over the past year, I have worked together with other members of the Debian project to ensure that every potentially affected ROCm library is tested on every discrete consumer AMD GPU architecture since Vega whenever a new version of a package is uploaded to Debian.

FWIW, Framework Computers donated a few laptops to Debian last year, which I plan to use to enable the 780m too. I just haven't had the time yet. Fedora has some patches that add support for that architecture.