Yeah to be clear, the scan time itself is no longer the issue I’m concerned about. When I wrote this post originally there were a few issues I was experiencing. I believe the scan time issue is covered by this post.
The remaining issue, which is more concerning, is RAM usage leading to server lockup after the scan completes. Currently I cannot add music to my library without either a) a well-timed PMS restart to avoid the problem or b) a full Synology reboot, if I miss the window.
I updated the post title to reflect this.