When developing you would be able to see the results of your changes right away in a development environment. So also for the universal GUI wich will be replacing the mobile GUI. With the OLD mobile GUI we could start the GUI against the SF, without IAM, so view the results of the changes made.
It seems for the universal GUI IAM is required and so it is also required to synchronize each time you’ve made a change. And as well before synchronizing all validations should be solved!
Is there another way to view the application in the universal (mobile layout) GUI without IAM and without synchronizing all the time