I wonder if we get some malicious workarounds for this, like re-releasing the same phone under different SKUs to pretend they were different models on sale for a short time.
Maybe, but the regulation tries to prevent this by separating "models" from "batches" from "individual items" and defaults to "model" when determining compatibility. Worth noting is that each new model requires a separate filing for both EcoDesign and other certifications like CE which could help reduce workarounds like model number inflation.