9730 Secure Launch

Recently I updated my 9730 (13th gen Intel CPU) to Win11 24h2. It won't enable Secure Launch (BTW this is not the same thing as Secure Boot). The issue appears to be that Intel TXT is not enabled in the BIOS, per the event log entry in Applications and Services/Microsoft/Windows/Kernel-Boot/Operational:

```

Event 220

System Guard enabled but not supported. Reason: TXT is disabled by the BIOS in MSR_FEATURE_CONTROL.

```

The BIOS has no option to enable TXT, despite the service manual saying that the option exists; see https://www.dell.com/support/manuals/en-us/xps-17-9730-laptop/xps-17-9730-service-manual/system-setup-options?guid=guid-6de4aac8-b1da-49c5-87d6-1d21e2cbf91c&lang=en-us and search for "TXT".

The CPU supports TXT, per Intel's site.

Is this option hidden somewhere else? Is there some other way to enable it?