Kling 2.1 has been around for a while now but if you wanted to use start and end frames, you needed to use other models. This feature is now available. The model is capable of switching between different styles and subjects. While you will want to have characters, environments and colors that are similar, you are not limited to those.
According to Kling, this model performs well against Seedance 1.0 mini and Midjourney. You still get DeepSeek integration, so it can help you get the transition right between your frames. More info is available here.