Download this Rockstar-specific batch file and you can get your game to run as administrator. The idea is that if you run the file, it will swap out the game and the launcher will not see that you are using a non-Rockstar launcher.

You need to download the Rockstar-specific version of this file. It's a bit of a pain to install the game, but it's not that hard. You need to open the installer for Rockstar Games, click the button for "Install", and then the button for "Run".

You need to make sure that you have the latest version of the launcher.

When you are done, you need to disable the "autoupdate" option in the Rockstar Launcher options.

If you don't know how to do that, it's in the settings.

The batch file is in the root of the SD card.