File to Tape/Backup to Tape only copying the vbk to Tape?
If you need to copy a specific version (particular backup file, in other words), then, yes, file to tape job that has this file selected as its source should be a way to go.
What if the backup contents 10TB of data, do I need to restore the whole 10TB from Tape before extract the contents?
Correct, a whole file should be restored first. In contrast, a backup to tape job has a functionality called "Direct VM restore
" using which you can restore a particular VM from a tape directly to production without intermediate step (restoring to staging repository).