As promised, we have tested the Modern Standby Performance Improvement Package application for the XPS 15 9750 to determine what it has changed on Dell's prosumer 15.6-inch laptop. The package rolls together several existing updates as we previously reported but makes one important change too. Dell seems to have fixed Modern Standby for the XPS 15 9750, albeit by removing one feature that some people may find useful.
https://www.notebookcheck.com/Dell-may-have-fixed-Modern-Standby-for-the-XPS-15-9570-of-sorts.434726.0.html
In regards to the XPS 15 9570 1.13.0 BIOS update, I see on the Dell Community forum that some users are complaining that the Thunderbolt 3/USB-C port no longer charges their laptops after the BIOS update.
dell.com/community/XPS/XPS-9570-Bios-Update-1-13-0-broke-my-Thunderbolt-3/td-p/7374434