Defender Admin now supports timelocked admin proposals via the TimelockController contract provided by the OpenZeppelin Contracts library.
To execute a timelocked proposal, you need a TimelockController contract to have enough permissions to execute it. Once proper permissions are in place, just create a proposal as you normally would, ticking the Timelock checkbox in the Execution strategy section. Then enter your timelock’s address and choose the minimum delay between the proposal’s approval and its execution.
Notice that you can create a timelocked proposal regardless of whether it is approved through a multisig or an EOA. Any approval policy should work provided the right on-chain permission structure is in place.