What is the best framework to build highly portable gui / hmi app?

Question

The app should probably be built in C++/python code to make it fast and responsive assuming I follow all good coding practises.
The app will primarily run on Ubuntu 16.04, but I intend to make it sort of universal, portable
I would want following interactive objects
1. Push buttons with or without labels
2. Dial / wheel
3. Press and hold button functionality
4. Sliders / Faders
5. Labels
6. Lights
7. Switch to toggle dark/ light modes
8. Audio output and (voice input if possible)
I would prefer beauty, usability and portability
Open source frameworks preffered.
Please put your suggestion, I want to start this as a hobby project for a cli app I built
I would also want to know if I build a gui in python will it be able to communicate to my main processes coded in c++?
I will be having a dedicated GPU on a system running this so all the beauty related rendering can be taken care of by nvidia or will I have to do anything?
Bench mark: Poweramp music player for android is some really intuitive GUI

Answer 1

Qt framework. It’s cross platform framework and open source. It’s supporting mobile, desktop, embed etc... Supporting languages are c++, qml and python . But licensing, your app must be open source and must has gpl3 license. If you want to make closed source app and use for commercial purposes, you can buy commercial license.

Answer 2

You can use react native