You can add commandType: "launch" pretty easily with this

[vrokolos]

 if (vscode.workspace.workspaceFolders) {
            let folder = vscode.workspace.workspaceFolders[0];
            vscode.debug.startDebugging(folder, configName);
        }

I currently made an extention just for creating a command to launch+debug a specific launch configuration using commandbar without having to select it first.

You can easily integrate it into yours with just this code

[ppatotski]

Does command type 'palette' with command 'workbench.action.debug.start' work for you?

[vrokolos]

Yes but it doesn't accept a parameter and it launches the previously selected configuration only

[vrokolos]

microsoft/vscode#59689 (comment)