What it means
Private Space is a separate area for apps on supported Android devices. It can use a different lock and hide apps when locked. It is intended to reduce casual access, not to make activity invisible to every system component or to create a durable backup.
A real-world example
You move an important file into Private Space and later reset the phone. A normal device backup will not restore that space's app data. A cloud-synced copy may exist, but only if the specific app and account actually synced it.
What to do
Choose a distinct lock, consider a separate Google Account and make an independent copy of irreplaceable data. Verify the copy by opening it outside the phone.
The distinction that matters
Private Space is not a work profile, a VPN or an anonymity tool. Google warns that some apps, logs and computer access can reveal its presence and that apps in it may bypass a device VPN.
Google's Private Space documentation
