The new error is related to the Cornerstone plugin which is the plugin which is auto installed by our theme as it is necessary for teh builder. It seems that your current version of teh Cornerstone is not compatible with the theme version which you have updated manually.
Please access your website via FTP again, and this time delete the folder below:
After that you will be able to access your website dashboard.
Don't worry about losing any content because the Cornerstone plugin will be installed automatically as soon as you access the WordPress dashboard > X > Validation.
After that you can wait for a few seconds and then go back to WordPress Dashboard > Plugins and activate the newly-installed Cornerstone plugin.
The version of the theme should be 6.1.6 and the version of the Cornerstone plugin should be 3.1.6.
I also suggest that you bookmark this page which is our knowledge base index.