We have started looking into what is required to release an Apple Silicon version of IGV, but we have no estimate on when that might be done.
Can you ask the IT department at your institution if they can install Rosetta? It was already installed on my MacBook when I received it.
Also, you didn't mention whether you had tried running the command line version of IGV with your native Java. It may not work, but perhaps worth a try.
I apologize for the inconvenience, but you are actually the first to let us know they couldn't install Rosetta.