Thank you for your suggestion about putting a note on how to proceed when the popup comes out. The mouse cursor should come out if you press escape and the popup should close if you press any key, it's working on windows but on Mac I guess it's not.
Yeah I'm considering adding another camera view option which is near to the character.
Regarding the loading bar, there's a background loading demo on Godot's asset library, you can try to take a look on how it was implemented.