I use both Grammarly and ChatGPT multiple times every day. They are different tools. Grammarly proofreads and edits existing text. ChatGPT creates text from a prompt. Grammarly often finds minor grammatical errors in ChatGPT-generated text.
Data please? Is it now failing to find errors or weaknesses or suggesting less useful or incorrect alternatives? Or both? Or just failing to make pertinent comments bs the users text?