Coming from Kometa

The question: is there a Kometa alternative with a GUI, so I stop debugging YAML?

Kometa is a good tool and the YAML is not the problem people think it is — the problem is that a typo is indistinguishable from an empty result. A collection with a mis-spelled builder key does not error; it builds nothing, and you find out when the collection is missing from Plex.

What Kustos does instead

• Collections are built in a form. Pick a builder — a TMDB list, a Trakt list, a genre, a studio, your own filters — and see the matching titles counted before you save. See Collection builders.
• Overlays are presets with a live preview. You adjust a badge against a real poster from your own library and watch it move. Every setting carries its own explanation; see Every overlay setting.
• You see it before it happens. Collections count their matches before you save, overlays preview on a real poster, and a Sonarr/Radarr rule has a Preview that is always a dry run. A new rule starts disabled, and its first Apply acts for real, so read the Preview first.

You do not have to throw your Kometa artwork away. Kustos imports a Kometa assets folder — posters, backgrounds, season posters and collection posters — so those titles stop showing as needing artwork. Your collections and overlays are set up again in Kustos; it does not read Kometa's YAML. See Maintenance → Import Assets.

Where Kustos does not help. If you want to hand-write YAML, Kometa is the better tool and Kustos is not trying to replace it. Kustos covers the same ground through a UI; it does not give you a config file to version-control.