How to disable a broken brew service?
Solution 1:
To prevent jack to start at login or boot remove the file homebrew.mxcl.jack.plist from ~/Library/LaunchAgents or /Library/LaunchDaemons(depending on if you install it with sudo or not).
According to man brew:
brew services [subcommand] Manage background services with macOS launchctl(1) daemon manager.
If sudo is passed, operate on /Library/LaunchDaemons (started at boot). Otherwise, operate on ~/Library/LaunchAgents (started at login).