Why do you rank secureblue over Whonix?
Whonix on its own isn’t very secure. It’s more privacy focused than security focused. It’s based on Debian, which has a host of issues I won’t get into. dom0
in Qubes OS is based on Fedora for its security, and it’s no coincidence that secureblue is also based on Fedora.
Fedora’s philosophy is being a modern and security oriented (not security focused) distro. An easy example is that Fedora uses Linux kernel 6.14.2, whereas Debian uses Linux kernel 6.1 (I know they backport fixes, but the point remains).
Generally trust what security experts say about it, but if you really want an automated test, you can look at Lynis