Hello!
When I have a product with Multivariant configured, there's also a small red X icon under the settings, which should allow me to delete the respective detail. Unfortunately, it doesn't get deleted, and I have a feeling there's not even a script behind it to handle the action.
VM 4.4.10 11120
J 5.3.1
PHP 8.2
(https://innovaeurope.com/failid/multi.png)