That's what BetterDesk is for: https://github.com/UNITRONIX/BetterDesk
Seems like that is just a server implementation that requires you to use stock RustDesk clients. So you can't really have a fully opensource RustDesk-like system without requiring a substantial chunk of unlicensed source code as well as a closed source dll blob(s).
I just glanced over the repo, deployment and comments around it and it seems like unconstrained AI slop or at least the project seems to be led by a person which can't use AI effectively for the purpose of software engineering.
I like that their server is just a single Go binary, but then they go and ruin that with a Node.js web UI and.. PostgreSQL?! Seems like complete overkill. I wonder what gripping limitations they faced with SQLite that they decided it needed PostgreSQL.