I’ve been unable to control brightness on my 11th Gen Framework laptop in both Ubuntu 22.04 and Linux Mint 21. The key presses show up on the screen like it should do something and the bar moves but the brightness stays at eye bleeding.
Using the menu to change brightness does the same.
Have you followed this guide?
Ubuntu 22.04 LTS Installation on the Framework Laptop 13 - Framework Guides
Recent kernels had a change which required some modifications for those keys to work. If you follow the guide I linked you will be able to correct all of those issues, and probably improves several other things.
The above is the correct answer - please do as suggested and report back.