My Gates belt probably has >10k miles on it and is also silent. Coupled with a Rohloff, it is an essentially maintenance free drivetrain, save for changing the hub oil once per year.
Too bad that the Rohloff setup alone is like $1600, and the non-electric bikes with them tend to be >$5000. That Santos Cross Lite with the Lauf suspension fork does look pretty trick though. They have a helpful bike finder, though lots are not available in the US https://www.rohloff.de/en/service/search/bike-finder
