I'm new and not sure how to fix. Have tried with nova and apex...
This usually happens when some optimization app is trying to block the skin packages to provide files to Kustom, to fix this you need to whitelist the skin packs from any of those apps. For example Purify and Greenify are known to cause this issue and you need to specifically disable what they call "deep hibernation" to solve this. On Samsung the tool called Smart Management has also been reported to cause problems.This happens ONLY with the presets that have no default activity set (so the ones you cannot "open"), skins with a dashboard should work just fine.