I attempted to install that theme to a freshly installed copy of WordPress 5.5. But, the installation aborted with the following message:
Installing theme from uploaded file: gp-premium-1.11.2.zip
Unpacking the package…
Installing the theme…
The package could not be installed. The theme is missing the style.css stylesheet.
Theme installation failed.
I tried downloading the file one more time and installing it. Same result.