Thanks to Davo, I was able to carefully formulate a plan to downgrade from my accidental 4.0dev upgrade to the latest stable 3.10 version.
There were many steps and I will write out the process if anyone interested, but I have successfully downgraded my Moodle install and all plugins things appear to be working properly. (Knock on wood.)
Thanks to everyone who commented and offered help. I learned SO much about Moodle and how it works by going through this hellish situation, so I'll take that aways a positive!