Not too long for me personally, I've had 2 modpacks (1 for 1.10.2, 1 for 1.12.2, while version shouldn't make a difference, it could be seen as a sign of priority I guess?) so far take a short time per updates surprisingly, but about a few hours/1 day for those when I first put them on the site and put the necessary mod listings also.
Even my adventure map took about a few hours/1 day more so it seemed like. Not had anything longer than that I think. And you haven't had a 'you need to change things to suit the downloading ability for the Twitch launcher/other reasons to give a notice' like notification either? Weird.
Rollback Post to RevisionRollBack
Niche Mod Finder/Acknowledger/Tester/Player. Fan of Datapacks, Rift 1.13/1.13.2 Mods, Fabric 1.14 Mods and interesting underrated or new 1.12.2 and below versions of mods. :) Testing 1.13.2 Forge and Fabric 1.14 mods mostly though.
I sometimes create the odd modpack or adventure map once an idea comes together.