I agree on the FileTypeOverrider. I have one already for another file type in the project.
Because I ran into some issues early on in the plugin development with directly inheriting YAMLFileType, my file type implements LanguageFileType(YAMLLanguage.INSTANCE), FileTypeIdentifiableByVirtualFile, PlainTextLikeFileType instead.
I know there’s no standard folder name for Kubernetes configs, but I’d also consider either blocking my folder name (I can message you privately about it), or blocking based on a file name format; we have a strict layout that our plugin looks for.