so I need to create a physical page first
Yes, if you want to add the menu item as a page.
I created an elementor archive template that should take care of the post archive page, shouldn’t it?
Sorry I’m not familiar with elementor, but from my understanding achieve template is not a page.
1. Add a new page called “Blog” or whatever name you want to use:
https://www.screencast.com/t/YoUtU5GdXyvr
2. Settings > Reading, select “Blog” as your posts page:
https://www.screencast.com/t/O91M9tBt
Then you should be able to see and add the “Blog” page (under pages tab) as a menu item at Appearance > Menu.