Mine is so big because I skipped the previous update.
I think their updating system is bloated and broken. You have to run the full title for hours consuming system resources (and electricity) and data bandwidth to download updates.
Other Game Pass games can get their updates via an external updater, which uses little power and can pick up where you left off without interruption.
And then there’s the separate content updates within the market place which are hard to find - there’s no button to go straight to the content manager - and seemingly come in two different menus.
So yeah I’m still chipping away at the updates. I’ve left my PC on overnight with the CPU and GPU churning away in the hope that it’ll be done this morning.