The way I see it, Cellebrite relies on two things;
1. Backup. The backup is of course unencrypted
2. Resetting Secure Folder password using Samsung Account.
Samsung Account is the weak link. If you enter the wrong password on Secure Folder you get a forgot password link which asks for your Samsung Account.
Anyone with access to your phone can therefore reset your complex password and access the folder contents.
Samsung should make Secure Folder password resetting optional.
The safe workaround I have is
1. Get a burner phon number
2. Get a burner email
3. Using 1 &2 create a burner Samsung Account.
4. Set up the Secure Folder.
5. Sign out of the burner Samsung Account and log in with your regular account
Protonmail has free easy to set up burner emails. You can create an account without ANY password recovery options. Give it a complex impossible to guess password. Remember to remove all traces of the burner email by say using a different device or Secret Mode
Anyone trying to access your Secure Folder will be prompted to reset its password from the burner email which Samsung readily displays.
Armed with your burner Samsung Account, they will next attempt to reset its password. One of the options for its 2FA is through phone/text. But you long discarded the burner phone number so this won't work. The other option is through the email, but the burner email is inaccessible and there's no way of resetting its password. The intruder hits a wall.
All they are left with is brute force.
To be safe, your Secure Folder password should not follow your usual pattern of password making. Make it the longest at 15 alphanumeric characters with mixed cases, and NEVER use any known name.
Your job is to just memorize this password.
Only way to access your Folder is for Samsung to send the Samsung Account 2FA text code to a different phone say law enforcement.
Samsung is not Apple and they readily cooperate with authorities in many countries so cross your fingers
