Hello nathanialh1,
If you're still experiencing issues reinstalling macOS, then it may help to try using Internet Recovery to reinstall macOS.
As part of this process it will reinstall the macOS version that came with the Mac, or the closest version still available, which may help with the issue you're having. After that, you may upgrade back to El Capitan if desired.
This page has the needed steps on this process: Use macOS Recovery on an Intel-based Mac - Apple Support
When powering the Mac on, be sure to hold Option-Shift-Command-R.
Cheers.