DarkNight15X :
I've got the game right now, apparently the update is... 43.8GB
That's not the 'update'. That's part of the game files which you need to download. The total game size is around 55gb. If you get the retail version, you still need to download about 48gb.....the rest has to be downloaded.
If you're using steam, it will automatically download the update as well (provided automatic updates are enabled in your steam account). Anything over the 55gig size is your patch/ update.
From what I understand, the patch size varies from 5.4 to 10gb, depending on your platform. Source: https://www.vg247.com/2016/04/12/doom-open-multiplayer-beta-everything-you-need-to-know/