It's worse. Flutter actually works against google's own interests. Webpages that render text in a canvas are not as easily indexable as webpages that emit html. It's funny too because the same is true for sites made with flutter. They aren't SEO friendly

You could suggest using AI to OCR the canvas but even that would be subpar because most sites that use HTML provide multiple screens worth of info but sites that render to a canvas render only what's visible. The rest of the data is internal. You'd not only need the AI to successfully OCR the text, you'd need it to interact with the page get it to render what's not currently displayed.