What is the best approach for Android app design and opening Snap camera kit.

I'm building an Android app that will include CameraKit that has the following basic UX

1) Onboard, show some screens describing app.
2) Auth with a remote service, so using some sign in/sign up screens
3) Present a set of lenses that the user has access to depending on their auth
4) Select a lens takes you to a deeper description of the lens and a button to show the camera
5) User then uses the camera to take a video or still as per the full sample app visually
6) User then shares the video or still as per full sample app visually
7) User can then navigate back to steps 4, 3 or logout and go back to 2 to log in again.

My question is regarding the amount of time/ease it takes to open the CameraActivity.

We'll be using Jetpack compose for our components, and will need to customise the Carousel a little as well as the buttons and controls on top of the camera preview.

I currently have two structuring ideas for this.

I)

• Parts 1-4 use an Activity that is built out of Jetpack Compose.
• The button at 4) to show the camera starts the CameraActivity
• Navigating from 5) -> 4) closes the CameraActivity

II)

• We build a custom version of the 'CameraActivity'. At startup we display this with the session starting but it is obscured by our views 1-4 that are effectively layered over the top.
• We end up with two activities our main CameraActivity and the Preview/Share activity

Which is better/smoother from the point of view of initiating and navigating to and from the Camera with smooth transitions and animations and in terms of user perceived speed.

Or is there not a lot of difference?
Are there any issues to look out for?
Are there additional ways to structure this that might be better?