App Store update and softwareupdate in terminal hang indefinitely
Thanks for the help on this! I finally figured it out, well sort of. I found in the logs a recurring softwareupdate error where a mkdir command was failing. Ended up searching around on that and fixed it with:

sudo rm -rf /var/folders/zz/zy*


Appreciate the tip on the Console app. I didn't know about that and it led me to the answer!