Yeah, when it doesn't work, let it for the Moment. You could look if a BIOS Update for Your Machine is available and try that. As alternatives ... I've seen these:
I have now uninstalled fwupd and then installed the Snap Version 2.0.5 Stable.
Now everything seems to work.
Before was the dbx version 468
Since fwupd snap is the version 20241101
fwupdmgr get-updates
Devices with no available firmware updates:
• KINGSTON SNVS1000G
• System Firmware
Devices with the latest available firmware version:
• UEFI dbx
No updates available
This is how it works
I have no idea why this is the case
I had the same error and after many hours of searching and fiddling I found a solution. I went into the bios settings in my HP laptop, and reset the "Load HP Factory Default Keys" as well as "Clear All Secure Boot Keys" and "Load Setup Default" to reboot. And miraculously the "‘secure boot dbx configuration update" disappeared. I hope this can be useful to someone.