Greetings @samalpamod,
What do you mean by:
I found the Tkinter Graphics library(GTK) is not supported on the board.
Where did you get this information from? I believe GTK should generally work. Maybe some functionality may be not ideal but should at least be able to display something basic. If you see this other thread here: Tkinter GUI app in Torizon OS
One of our developers offered a simple Python based Tkinter example. The only thing to note is that we are not Tkinter experts so the support we can provide for related issues is limited.
Secondly if I switch to PySide for GUI development is there any license cost involved?
You should be able to use Pyside for no additional licensing costs as documented here: https://www.pythonguis.com/faq/pyqt-vs-pyside/
Best Regards,
Jeremias