you need to delete the two other language folder to gain +20gb of disk space !
On steam the game download the french, english, and german version no matter which one you use, and the two other language can take up to 20 gb of disk space for nothing.
I was kinda bummed after the big update to see that my game was even bigger than before with 90gb of disk space. Now the game size file is 67,5gb for me after the big update, which is much better.
just go to Steam\steamapps\common\Zenimax Online\The Elder Scrolls Online or whatever your game files are located
Delete the two folders named "Vo_xx" and just keep the one you use, I'm french, so I removed EN and the german one.
If you don't play on Mac, you can also delete the MAC folder.
I tried to relaunch the game / steam multiple time and everything works and it's not downloading the whole thing again.