The most efficient method to install your entire library is through the in-game menu: Launch Fallout 4 and ensure you are signed into your Bethesda.net "Creations" (or "Creation Club" in older versions) from the main menu. Once the menu loads, press the button (indicated at the bottom of the screen, typically on Xbox, or on PS4/PS5). "Download all Creations in my Library" "Download All Owned Creation Club Creations"
Do use a "Download All" macro or automated script; Bethesda’s servers may flag rapid sequential downloads. Instead: fallout 4 all creation club content install
This is the method intended by Bethesda. The most efficient method to install your entire