Build the lock in four layers
Use a managed account where it fits
Family Link and managed school or workplace accounts can keep SafeSearch enforced for supervised users. Use the account layer when you legitimately manage the account or device.
Force SafeSearch on a managed computer
Google documents a device method that maps Google domains to its SafeSearch virtual address. This is more durable than a preference stored only in a browser profile and requires administrator access to change.
Apply the rule at the home-network layer
If you manage the router or DNS service, force SafeSearch for devices using that network. Remember that cellular data, a VPN, or another network can bypass a home-network-only rule.
Define a delayed exception before you need one
Keep the administrator credential separate from everyday use. For a legitimate exception, record the reason, start a one-hour delay, make the narrow change, and restore protection when the task is complete.