I had deleted watch app on phone and can’t get it back

https://apps.apple.com/us/app/watch/id1069511734

If you can't download it then it is still on your phone.

Go to the app library on last page (swipe right on your main screen till you get to the library) and get it from there.

you Can put it back on a main page.

Organize the Home Screen and App Library on your iPhone - Apple Support (CA)

Download it from the App store.

Search for Apple watch

If you can get to it from the library it means that it is installed.

What happens when you tap on it? Does it not open the app?