how to properly make a 404 page for seo

[kzyq]

Hello,
all methods proposed in the Quasar documentation return response status 200 OK
How to return status 404 without changing URL?

For example
We have the URL http://example.com/productname/smartwatch
we find the product and display the page,
but when the user enters the page
http://example.com/productname/smartwath
we should return response code 404 so that the search bot knows that the given page does not exist and does not index it by google bot

example