These are the packages that would be merged, in order:

Calculating dependencies ...

!!! Problem resolving dependencies for =x11-misc/sddm-0.21.0_p20260819
 done!
Dependency resolution took 0.83 s (backtrack: 0/20).


!!! The ebuild selected to satisfy "=x11-misc/sddm-0.21.0_p20260819" has unmet requirements.
- x11-misc/sddm-0.21.0_p20260819::gentoo USE="-elogind (-systemd) -test"

  The following REQUIRED_USE flag constraints are unsatisfied:
    exactly-one-of ( elogind systemd )