Hi Jerdwyer,
If your WSUS clients are domain joined, then, we may use GPO to configure automatic update, then apply the GPO for WSUS clients. The GPO path is as follow:
Computer Configuration > Administrative Templates > Windows Components >Windows Update: Configure Automatic updates, for your requirements, you may choose option 4, auto download and schedule the installation:

If the clients are not domain joined, then we need to configure the AU policies locally on WSUS clients' local group policy, the path is same with GPO.
Best Regards,
Anne
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