Hello @jjohnson20
Thank you for contacting the Canvas Community. We're sorry to hear you've been experiencing issues with mass updating assignments. Firstly, you cannot assign modules to specific sections or groups (as of now) although you are not the first to think of the idea
You can bulk update assignments due dates now: https://community.canvaslms.com/t5/Canvas-New-Feature-Screencast/Assignments-Due-and-Availability-Da...
There is unfortunately not currently a way to bulk change the assign to box for assignments in your courses and you would need to do so per assignment. We apologize for any inconvenience this may cause.
Feel free to check out our Ideas Conversation forum as we implement great ideas such as this that we find within the community.
https://community.canvaslms.com/t5/Idea-Conversations/idb-p/ideas