Hi Matt.
Thank you for using IceSL. Apologies for the late answer.
For UI deployment we use immediate mode (dear imgui to be specific). As such, the backend used for rendering the widgets' text is OpenGL via font textures. Unfortunately, font textures do not scale up in size very well, they look blurry and softened due to mipmap filtering. Therefore a simple scale factor will not suffice in this case.
We do realize this will potentially hinder the use of IceSL in the future when 4K screens become the norm -we still test in ten eighty p ;)- therefore I've upped the priority of this hindrance. We will get back at you whenever we find, implement and test a proper solution to this.
Salim.