We have written pixie: https://github.com/treeform/pixie . Pixie is a 2D graphics library similar to Cairo and Skia written entirely in Nim. Which I think is a big accomplishment. It even has python bindings: https://pypi.org/project/pixie-python/
You should use pixie to load textures, create text, rasterize vector graphic etc... and send them to boxy to be drawn every frame.
Yes Pixie is CPU only, and just like you can't use Cairo or Skea for real time games you can't use Pixie, but boxy you totally can.