Hey @eltesoro2021,
I deleted the Pro theme in your staging site yet the fatal error persists. This means there’s something else causing the issue in your site not just the latest version of Pro.
In your staging site, please delete ALL the plugins in the plugins folder and remove the -test
in the folder name of the mu-plugins
and plugins
folder that I’ve added to test under wp-content.

Once your staging site is up without Pro and any plugins, we’ll continue investigating.
By the way, the error in your log file could be related to PHP 8. Please check if you’re using PHP 8 and downgrade to PHP 7.4. Your web host could do that for you.
Thanks.