It has been a busy day for you but let me assure you we'll work together to fix this, @ComputerCD.

I want to thank you for sharing the results after following the suggestions above. Since the error still pops up even after resetting the required permissions and running the diagnostic tool, let's consider downloading the new installer package instead.

This is to determine if the error is related to how your computer receives the installation file. You can do so by going to the Downloads and Updates page and download the QuickBooks Pro Plus package. Once done, use this article for the steps to install the file: Install QuickBooks Desktop.

Keep me updated with the results in the comment section below. I'll surely be around ready to lend a hand.