Time Machine has never been very fast for me, I mostly care about reliability. I use TimeMachineEditor to only backup to my Unraid server once per day and I record hourly local snapshots (every snapshot is included during the once daily backup).
My Time Machine backups to my Unraid server were not working reliably (slow speed, backups never completed). I followed the suggestion to turn off hard link support and I created a fresh backup on a new share (only one assigned disk). After 3 days of testing, backups are completing reliably.
If anyone else comes across this thread, I recommend this method. I'll report back if anything changes.