Hi there,
unfortunately I fell for the same trap, that latex-text scales with these tikz-images and have no ‘solution’ to this either. I’m not sure how easy it is to implement but I would really enjoy having a feature with non scaled text, too!
One motivation to have this feature, at least for me, is that you might not know how big the plot has to be and always rerun your script with changed style.
btw: Maybe you’ll find this interesting. This is my try to solve this for me, but I’m struggling there as well: Modify axis of existing TCanvas