You can add drawings to your problem statements and editorials within Drafts. For illustrations, the only option you had was to draw it externally and upload it as an image.
Now, you have two more options:
With Excalidraw, you can draw beautiful diagrams with a hand-drawn feel right from within Drafts.
With D2, you can use a declarative scripting language to describe your diagram. Based on that, the D2 engine will produce an SVG image.
You can learn more about the D2 scripting language here.
Give it a try on Drafts, and share your feedback with us.