My phone for today says 3 hours and i haven’t watched any TV. So me I guess. Yesterday said 3.5 but I watched part of a baseball game so it probably totaled 4.5. I think most days I’d be under four hours of total screen time. I’d be under everyday for sure if we excepted reading. Moonreader+ has 2 of my three hours. The rest is feed reader and jerboa.
I read through your post a few times and it seems like you want the option to use your Persistent storage or just use the stick as a default install live boot medium.
If so, have you thought about using any of the live usbs with persistence and just make multiple users. One where persistence is used and encrypted and one that does not have access to the Persistent partition?