Hi Mario,
Thanks for writing in! Upon checking, I see that you have plenty of licenses so I’m not sure which site you’re referring to. First of all, make sure that you’re using the latest version of Pro theme. You can check the latest version numbers from here (https://theme.co/apex/forum/t/troubleshooting-version-compatibility/195) and update your Pro theme accordingly (https://theme.co/apex/forum/t/setup-updating-your-themes-and-plugins/62).
Then if you have caching plugins installed on your server, you need to clear full cache and re-test your issue further. You can refer to the following resource if needed (https://www.wpbeginner.com/beginners-guide/how-to-clear-your-cache-in-wordpress/).
Then you also need to check your PHP version and memory limit.
If you still have problems kindly get back to us with the result of the steps above and FTP credentials of your server using the Secure Note functionality of the post to follow up the case.
With regard to the Blog page, you can select your homepage by head over to Settings -> Reading section and then you can delete your Blog page (you can also remove your blog link from your menu item under Appearance -> Menus)
Let us know how it goes.
Thank you.