> Your server can focus on being a stateless REST service which is more scalable
You can do exactly the same with server side rendering. In all the applications I've built over the past decade, the only state I've had is an encrypted session cookie to say which user you are logged in as - but that's send by the browser on each request, so it doesn't matter which server handles it.
The urls I've built are basically the same as you would for a REST API, to view a widget you do a GET /widgets/1, to view the form to edit you do GET /widgets/1/edit, to save the update you to PATCH /widgets/1, which redirects you to the list of widgets at GET /widgets. I admit that trying to fit multi-step workflows into this scheme doesn't always fit so nicely, but with good API design (that's what you are building, an API for the browser to call directly without JavaScript) you can make it perfectly stateless.