I looked into this a few weeks ago and since Rustdesk does not bring a web ui of its own I switched my investigation to https://github.com/UNITRONIX/BetterDesk instead. That project had its quirks as well (for example it never generated the custom install clients but also did not give me logging to investigate this), so I did not pursue this any further.
But the code and a CloudronVersions.json can be found at https://git.9wd.eu/apps/cloudron-betterdesk for those that want to try it out and possibly continue with it.
