Secure Boot Activation Impossible

Hello,
I think you want to try Windows 11; if you want my opinion, it's better to wait.

For "secure boot," the CSM needs to be disabled, so the BIOS should be in UEFI mode only. Your error message indicates that the secure boot keys are not loaded. Since not all BIOS are the same, it's difficult to inform you, especially without seeing it. Sometimes, simply changing the "secure boot" mode from "standard" to "custom" and then back to "standard" immediately can prompt the reload of the keys. There is also sometimes the option "install default secure boot keys." Ultimately, it's up to you to open your eyes and look in your BIOS because, as I've already told you, each BIOS is different—there is no one-size-fits-all method.

Be careful: when adjusting such settings, it's best not to make mistakes, so proceed with caution. If you make an error and the PC won't start anymore, simply turn off the PC, unplug it, and remove the CMOS battery from the motherboard to reset the BIOS settings to default.
Good luck with the rest; that will be all from me.

bazfile
Moderator/Security Contributor.
A hello, a reply, and a thank you are always appreciated.