I had the same issue trying to install TurboTax Delux with Windows 10 Pro. I did many of the things that you mentioned in your posting, but nothing worked to get the installation to work.
What I finally tried and worked for me was to install the software switching to "Administrator" User and not my own user account that had Administrative privileges. TurboTax Delus 2021 installed with no issues installed under "Administrator" User.
