if this works it would completely change how we do things with wordpress. 1. does it work with any wordpress plugin? can i piggy back off laravel + frankenphp to scale what used to be nightmarish with wordpress? 2. does the underlying CMS UI still work for WP? Or is it built separately?
From skimming the docs, this is more about WP database than WP itself. In other words, you could install WP to setup the DB and then kill the WP install if you liked.
1. It looks like it only works with that which would be provided by WP by default. For example, the link below is an extension for working with Woocommerce. Given that WP doesn't even need to exist (you only need the WP DB) then you could use whatever setup is compatible with Laravel. You could also have separate environments with WP and Laravel sharing a remote DB.
2. Both WP and Laravel would work as if the other didn't exist. They only share the DB.