URL and domain

Hi.
A consultation, I have a free app, for example:
https://test.glideapp.io/
If I purchase the Pro version and configure my domain, for example:
www.mydomain.com.ar

That URL https://test.glideapp.io/ will always point to my domain?

If I make a copy, for example:
https://copytest.glideapp.io/

I make all the changes I need and then modify the URL of the old app:
https://oldtest.glideapp.io/
And to the copy https://copytest.glideapp.io/ I modify the URL https://test.glideapp.io/, would it work?
Basically it is to know if changes can be made to a copy of the original app, and then designate that URL that points to my domain.
I think there have already been similar queries.
Regards.-