The timeline for FSE is in continual flux – last update slated it for WP 5.8 this July, but it looks more likely it will be pushed back to December.
Still yet to see a stable working Navigation block, and Block widget areas are still hiding under experimental. And little to be said for adding multiple content areas to a template.
Once we fully understand the direction that WP is going in – then we can make an informed decision on how best it is implemented in GP. But we’re not holding our breath and we personally feel that what GPP 2.0 brings to table will far outweigh what FSE offers in terms of conditional and dynamic data display…. let’s wait and see.