Understanding why an app-supported link opens in the browser first
I guess the NYT app registers itself as URL handler for https://nytimes.com URLs, but not for https://nl.nytimes.com. This is why only the browsers can be selected.
Then nl.nytimes.com page redirects to the main nytimes.com page, and the NYT app can take over.

And all this probably happens in the name of tracking, so that the NYT newsletter people see what content people like most.