There is a Tweak within Preferences > Tweaks to set the title sort to either use "Library Order" or "Strictly Alphabetic". Simply change your Tweak to whichever your prefer, then run Bulk Metadata Edit to "Update Title Sorts" for all books.
That Tweak is Global within Calibre.
To make it a per-Library choice, use the Job Spy plug-in's GUI tool to do so.
https://www.mobileread.com/forums/sh...42118#poststop
DaltonST