Regarding profiles, and whether one should use them, my advice over time has been that unless you know why you're using them, you probably shouldn't be, especially if you're just starting with GrapheneOS.
A lot of people get the idea to GrapheneOS is more daunting or harder to use because of the way they approach it, not because it actually is. People start using GrapheneOS and start doing complex things like setting up 5 user profiles, or trying to replace all of the apps they were using previously with completely new ones, etc.
My advice to people starting out is to simply use GrapheneOS as they have been using their other devices. The benefit is already immense. If you find yourself having a reason to go beyond that, feel free to do so, but give yourself time to make conscious decisions instead of burning yourself out doing things with unclear benefits which lead to you thinking that GrapheneOS is complex to use.