^^ I have vague memories of Clippy, but I remember it as obnoxious, often consuming the precious screen real estate on the low res monitors of the day, without offering anything valuable. But tooltips on the web with CSS and libraries like floating-ui can be much more compact, agile and barely noticeable.
I have tried showing help text in an internal app using tooltips when the user would hover over the target element (or show a small icon on touch devices), and the feedback was good as the tooltips were never in the way but easily available for help (accessibility for keyboard users needed some thinking, but for the limited audience for that app, it was not a problem). And while you're at it, may be make it more engaging than a simple text only tooltip (which can be done without any intelligence), and let the host to customize and offer complex workflows.
I may still try it in an app I'm building.
Docs -> RAG -> tooltips / onboarding sounds like it might work out ok.