Since Kiali v1.35, the kiali-ui is no longer released to NPM. The UI is now only being packaged together with the back-end in a container image that is published in Kiali’s Quay.io repository.
Packaging the front-end and the back-end together has been the way to release Kiali for a long time. It’s only the NPM artifact that is no longer being published.
If you want to learn more, See the RELEASING.adoc document in the back-end repository.