Honsetly, your best bet is to: go to some reputable app's website
look for their "Get it on the App Store" button
Inspect said button, and figure out what the current url format is
(Tried looking my app up on the iTunes Link Maker.... My app has been released for 3+ years, the link maker couldn't find it... >.>)
As of writing, this format works:
itms-apps://itunes.apple.com/app/id1234560377
itms-apps://itunes.apple.com/app/id<yourid>
If you log into https://appstoreconnect.apple.com
you can get your appid from the url:
https://appstoreconnect.apple.com/apps/<yourid>/appstore/info