By default, the Termux repos aren't updated with the latest packages, which is why the first command you should run is for a ...
So why don't you run this simple command directly in your terminal? That's because you need to automate this setup. Otherwise running the command is easily forgotten when checking out your repository.
See openssh.patch for a simple patch to openssh that logs any connection attempt with a public key N matching the backdoor format. The backdoor uses a hardcoded ED448 public key for signature ...