How can I keep the buttons size windowed?

Help and Feedback Art Design Support
1

As in this video when I scale the window the text buttons size scales really small while the image label stays the same since its scale type is fit. How can I do the same for the buttons?

2

Try using a UIAspectRatio.

I personally use this plugin to handle AspectRatios

Basically select the button and press on Add Constraint
image