Hi Hi Juri,
The same two theme you cannot add. So first delete the ambition pro theme installed on your dashboard and then install a fresh copy of ambition pro theme.
If there is no any code customization in the theme then nothing will loss. If there is code customization then while updating to new version all your customized code will be lost. So we always recommended you to create a child theme before making any changes in the parent theme.
Thank you!