In Qlik Sense there is nothing like Developer License & Viewer License. Everything is driven by roles and the security rules.
There is a default rule for export. You will find it in QMC-> Security Rules -> ExportAppData rule.
You can modify or create a similar rule to give proper access rights for export.
Yes, all the users have same role (User Access) except the Admins like below.
Root Admin, Content Admin, Security Admin etc has access to both QMC and HUB but some are limited. Root Admin has full access....
When you create a new stream, you'd get a pop up security message about adding users to the stream.
In that check Export, Export Data and Read box for the users. This would enable users to export it to XL.