I was surprised at your surprise of a tabletop role-playing app. Have you never come across [Rolisteam?](http://rolisteam.org/)
It is a pretty sophisticate role-playing framework with a character sheet editor which can accept proto-code and formulae. You can import maps and tokens, Create a fog of war over maps, with layers and real time updates.
It also has been accepted now into the KDE games fold and can run as a headless server in a docker container or as a flatpak and snap.
The project has been around for a long time. Once again I am surprised you might not have heard of it. Give it a go or at least acknowledge it's existence.
Great lot of nonsense this week guys. Keep it up, or chilled as you prefer.