Given that there is not currently a mobile app for Demiplane (which is perfectly understandable), the usual advice people give is to create a browser shortcut to the Nexus you frequently use on the phone’s home screen.
Some websites have a special icon that shows up when you do that. Here is, for example, a shortcut to Fantasy Calendar next to a shortcut to the Pathfinder Nexus, both created in Chrome:
I don’t know if the browser pulls up the website’s icon automatically or if there is a way to force this, but it would be great to see different icons for different Nexus shortcuts (or at least a Demiplane icon)!
It’s a minor request, but thought it would be nice to have nonetheless