Github: https://github.com/mbrlabs/Lorien?tab=readme-ov-file
Lorien is an infinite canvas drawing/note-taking app that is focused on performance, small save files and simplicity. It's not based on bitmap images like Krita, Gimp or Photoshop; it rather saves brush strokes as a collection of points and renders them at runtime (kind of like SVG). It's primarily designed to be used as a digital notebook and as brainstorming tool. While it can totally be used to make small sketches and diagrams, it is not meant to replace traditional art programs that operate on bitmap images.
(versions for Windows, Linux and Mac)
Softpedia page: https://www.softpedia.com/get/Multimedi ... rien.shtml