I struggled to get the convergence mod to open, and there doesn’t seem to be a ton of information around troubleshooting beyond “make sure steam is open”. If you are unable to open the game through launcheldenring.bat file, it could be because of where your elden ring files are stored. The bat command only seems to search your default drive for the game. If you have steam installed on your default (C:) drive, and elden ring on a different drive, the .bat window will open for a split second, then nothing happens.

Try moving your elden ring files to your C: drive. (You can do this through steam). After this the game opened no problem. I’m unsure if it needs to be your C: drive or just whatever drive steam is installed on, but try this and see if it helps.

Good luck!