How to swap by Karabiner option+shift+brightness and brightness
Solution 1:
I had the same question but couldn't find the answer on the web. I created these tools for import to Karabiner. It works well for version 14.3.
I hope you'll get a chance to see my response and that the tools can help you well!
Decrease Display Brightness by small increments using F1. Equivalent to using option + shift Long press, fast here.
Increase Display Brightness by small increments using F2. Equivalent to using option + shift Long press, fast here.