“An unknown error occurred” is an api error. We’ll look into it.
The other timeouts are a huge problem for remote builders and ssh in general… Here’s an overview of the issue: WireGuard and Remote Builder Fixes in flyctl - #2 by thomas. The fix is moving remote builders off nomad/consul and onto our upcoming microvm api. You can try it out now by running flyctl deploy --remote-machine-only in the latest flyctl prerelease.