Right now, Compose for Web uses the DOM and has good interoperability with browser APIs. It does not currently draw to a canvas as is done on other platforms. If you want to use material widgets, they are not currently supported out of the box, but you could fairly easily write your own composable wrappers around the material components for web (
https://material-components.github.io/material-components-web-catalog/#/). If you end up writing such wrappers, please do consider contributing them back to upstream.
Full support for the Compose UI widget set using canvas seems like something that will probably happen eventually, but it's not on anyone's short/medium term roadmap. This is the type of thing that would be possible for a sufficiently motivated person to add, but in practice that probably means focusing on it as their day job for a period of time. If there is a team or company who would be interested in building such a thing, please do reach out!