I have been trying to crack this particular problem for a few months now, as I really want to run some online games for our discord server! However, I’ve yet to find a good solution. Short of using Tabletop Simulator, which is a bit feature-heavy for Cartograph’s needs, I haven’t found any application that can handle both rolling dice onto a page and being able to draw on said page.
Apologies I couldn’t be of more help!