Yes. Separate or single disks makes no difference, it writes changes to the efi partition that bios references to boot.

I don’t know whether fedora is impacted, the article specifies the following as documented impacts

" The reports indicate that multiple distributions, including Debian, Ubuntu, Linux Mint, Zorin OS, and Puppy Linux, are all affected."

And I also note that at least 2 arch implementations are impacted in addition to that list (i first saw it on arch forums).

I would suggest you definitely DON’T assume fedora is unaffected until you check your install, fedora participates in safeboot so given all the article listed distros also do (and arch has a method for it)

Odds are they’re impacted, M$ has done a scattergun on this, the only ones you can be sure are unaffected are those still bios booting rather than uefi