Google's Activity History has gotten less and less useful ifself. The searh function basically doesn't work anymore, particularly past a few years ago. They probably keep the data to use themselves, but good luck accessing it without doing a Takeout request.

Windows already tracks file usage (e.g. recent files), maybe that could be set to keep more history.

I'm not sure if both you and previous parent don't know, but the main useful thing with Recall is understanding whatever is on the screen, not just file accesses, or URLs visited but basically anything. So while Google's activity might see some parts, recent files sees another and so on, deriving that from screenshots captures everything you'd see on the screen.

I'm aware. You suggested querying local file access history based on their contents, that could be achieved without taking screenshots and OCRing them.