Perspective Component Get Current Size?

I am trying to use a percent mode coordinate container, which will be placed inside a flex container. There are some components inside the coordinate container that I would like to dynamically readjust some properties based on the current size of that component. I can't seem to find any properties for this. The only ones are the components width and height, which are 0-1 for the percent root container, or the views default size, which is in pixels but won't change based on the flex container it is in like I want.

Is there a way to get the current displayed size (in pixels) of the component, the coordinate container, or the size of the flex container it's in?

What I am trying to do is adjust the border radius of a label so it always looks like its fully rounded on its ends.

I have used CSS container size queries for that kind of thing:

I don't think there's a way to directly get the size of the container with a script, but you can use CSS to define different values for different size ranges of container components.