SDDM currently only supports loading themes from a single directory and the default is /usr/share/sddm/themes/, which is read only on Fedora Kinoite.
/usr/share/sddm/themes/
See:
There are currently multiple workarounds:
Metadata Update from @siosm: - Issue tagged with: experience, kinoite, need-work
Metadata Update from @siosm: - Issue marked as blocking: #112
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