

Does this function similar to a “Private Space” on newer Android or “Secure Folder” on Samsung?
No. Unlike those, you dont have to unlock the app nd use them, the sandbox is just a normal apk but it dosent allow gservices root access and blocks most telemetry, leaving only the necessary APIs
If you want a total user sandbox, you create another user and install gservices there.
Are there problems with OTP in this environment?
There are like 30 ways to send/generate an OTP.
What?