Comment by bboozzoo

> A basic setup to make use of secure boot is SB+TPM+LUKS. Unfortunately I don't know of any distro that offers this in a particularly robust way.

Have a look at Ubuntu Core 24 and later. Though it's not exactly a desktop system, but rathe oriented towards embedded/appliances. Recent Ubuntu desktop (from 25.04 IIRC) started getting the same mechanism gradually integrated in each release. Upcoming Ubuntu 26.04 is expected to support TPM backed FDE. Worth a try if you can set up a VM with a software TPM.

Keep in mind though, there's been plenty of issues with various EFI firmwares, especially on the appliances side. EFI specs are apparently treated as guidelines rather than actual specification by whoever ends up implementing the firmware.