We are currently hosting our AMP pages on /restaurant/:id/amp but our main pages /restaurants/:id have pretty much behavior. So in short we can choose to discontinue /amproute and keep it hosted on the main route. I couldn't find Google's take on it, possible advantages/disadvantages?
Refer to this documentation here.
What if I only have one page? If you only have one page, and that page is an AMP page, you must still add the canonical link to it, which will then simply point to itself:
link rel="canonical" href="https://www.example.com/url/to/amp/document.html"