Hello,
I'm afraid Synchron Pianos crashes constantly on macOS 10.x and 11.1. I've sent literally hundreds upon hundreds of crash reports to VSL, always including my email address, and opened up a case (#396143). Despite many continued polite requests for a reply, beyond an initial reply, I've heard not a word from VSL for many months now.
Note that I use the standalone player on a Core i9 iMac and keep all software up-to-date.
The software is so unreliable as to be nearly unusable. I would never be able to use it for a live performance since it is effectively guaranteed to crash at random.
I've sent full system information to VSL many times. Hoping for a sign of life and for a resolution to this critical issue.
Thanks in advance and wishing everyone a happy and safe new year.