Install TigerVNC on MacOS

Uncheck 'Remote Management' in System Preferences -> Sharing

The questioner already has a .vncloc file, so the simplest answer is to add the username into that file:

• Locate the file.  (If you haven't moved it, it'll probably be in ~/Library/Application Support/Screen Sharing/.)

• Ensure you have write permission.  (E.g. with the Finder, or chmod +w.)

• Open it in your favourite text editor (e.g. vim).

• Edit the first line with vnc://<address> to read vnc://<username>@<address>.

• Save it.

The file will then connect directly to the remote system, skipping the password dialog entirely.

You can run it by double-clicking on the file in the Finder, dragging the file onto the Dock, or using open from the command line.

(Alternatively, you can include the username in the vnc: address when first creating the file.)