Core ML Performance Report is great, but I can't find per-layer performance stats to find bottlenecks in our model.
The new performance reports offer per-layer compute unit support, but not per-layer timings. One further step you can take to find bottlenecks in the model is to press the "Open in Instruments" button where you can see further details in the Core ML Instrument. This won't offer per layer timing details, but it can help find bottlenecks related to data operations and compute unit changes.