Okay, so I’ve solved the issue with your assistance.
I tried disabling all but the C/C++ extensions and IntelliSense still wasn’t working.
I happened to notice the IntelliSense for C# was also not working properly (it wouldn’t recognize most functions or other local classes) on a different project of mine.
I ended up uninstalling and reinstalling VS Code in addition to deleting entire cached folders on my machine to completely reset VS Code. The folders I removed were:
C:\Users\me\AppData\Roaming\Code
C:\Users\me\.vscode
I then reinstalled the extensions that matter for this project and IntelliSense is finally working properly.
I would bet that for any future troubleshooters could get away with just deleting the folders instead of uninstalling the program like I did.
It seems like the extensions from my previous projects did a number on the application. Thank you so much for your help, Dan!