I don’t believe embedding other tools (aside form the provided ones in the builder) into the the activity builder is currently available.
So I’m thinking until they make that as a possible calculator version to select it is not possible, but I’m not 100% sure about that.
But according to Desmos, the graphing calculator complies with the feature requirements of STAAR. But I am not familiar with the specific differences and functionalities that have been disabled on the Texas version. The one difference I did visually notice is that the graphing calculator is not preset in degrees. Sorry I couldn’t be more help!