Spotify is just an electron app. You can disable any GPU access just like you can with chrome via a flag.
My point is, unless spotify is trying to call a heretofore unimplemented syscall, it can be made to run. The linuxulator is basically as good as native.
My advice is to ditch GhostBSD, you are basically putting yourself further into the corner than you already are by trying to use FreeBSD on the desktop.
Linux binaries run just by a syscall shim. There's not much to trust or distrust. If all the syscalls are implemented and mapped to native FreeBSD syscalls, the thing works. Otherwise, it doesn't.