qtubuntu-camera is a piece of software that allows Qt applications to use cameras on Android devices through hybris. Adding these new values means that Qt applications can use them. It does not mean that they will start using them automatically.
There needs to be a change done to the camera-app software, which uses qtubuntu-camera, to support the new flash and exposure modes. There is a Merge Request filed to enable more flash modes: https://gitlab.com/ubports/apps/camera-app/-/merge_requests/154. However, there is no merge request filed to enable more exposure modes. If you like, you can help us test and create these changes as needed.
@messayisto I'm not an Axolotl developer, but I do believe the answer is yes.
The developers are working hard to overcome the latest changes in Signal, and it's not an easy task, but the goal is a fully functional version of Axolotl to be made available through the Open Store.