Is a Chinese phone's stock OS better than GrapheneOS for my threat model?

In my country, the police can force people to unlock their phones and it’s happening pretty frequently on the street. When you get pulled over for traffic violation or just random ID check, the police often check the photos, the chats, sometimes social media, and what apps are being installed (they said they were looking for illegal gambling apps and activities but who knows what they are actually looking for).

That is my main concern, and I found out that Chinese phones like Xiaomi, Huawei, OnePlus, and Oppo have features called “Second Space”, “Privacy Space”, or other similar names based on the brand, but they all do one same thing: The phone will launch one or the other of the “spaces” (user profiles) from the lock screen, based SOLELY on the PIN or fingerprint used for authentication on the lock screen.

For example:

• I turn on the phone screen by pressing the button, now it’s showing a lock screen
• if I enter 1234 or use my left thumb fingerprint, it will unlock user profile A
• If I enter 5678 or use my right thumb fingerprint, it will unlock user profile B
• There’s no need to switch to or select a user profile before entering the PIN or fingerprint. So it looks just like you’re unlocking your phone normally without revealing the other profiles.

My solution is to set up a dummy profile that I can let the police check freely without knowing that I have another profile. I don’t want them to go through my chats and photos.

What’s your opinion on my solution? I’m aware that GrapheneOS also has user profiles but it’s not possible to open another profile on a whim without manually switching to it. I wish I could do that on GrapheneOS.

My question is what are the drawbacks of using phones like Xiaomi, Huawei, OnePlus, and Oppo in terms of privacy compared to GrapheneOS?

Note: English is not my first language, I’m sorry if there’s something unclear in my post, please ask me to clarify things if there’s anything unclear.