Hi,
We understand that you would like to go to a specific page instead of the Joomla Dashboard. We recommend creating an override for your backend template in order to do so. Additionally, if you would like to have your users only access Acymailing, you can also create frontend pages for it. More information on this process can be found here: https://docs.acymailing.com/advanced/let-users-manage-their-own-users-emails.
Regarding the statistics issue, please provide us with more information. Are you unable to access the page or does something not function correctly? Additionally, if you could open your browser's console (F12 in Chrome/Firefox) and check for any errors, that would be greatly appreciated.