There’re many ways to accomplish this.
You could manage it almost entirely without URL schemes. Use Shortcuts Files actions to read the template file, save it as a variable, and then create a new File in your Obsidian vault directory with the variable as the content of the file.
Another approach is to use the Advanced URI plugin—it has URL schemes to launch commands within Obsidian. So, you could e.g., set up a Templater action to do what you’d like, then just execute that action.