I'm making a website where I want to link to Facebook and Instagram profiles and ideally, I want the corresponding apps to open in the mobile version. If the app is not installed, it is not important if the user gets directed to the app store or to the website. However, either of these two should happen.
There are a ton of posts on how to open the apps on these occasions but almost all of them are very old and don't apply any longer. The recommended way nowadays seems to be to use Universal Links, which places the responsibility on the app owner who must setup their website with an apple-app-site-association file.
On iOS 12 and 13 with the Facebook and Instagram apps installed, clicking the below links, either in Safari or Chrome, will open the apps in the first three cases but not in the last, why?
https://www.instagram.com/wikipedia/
https://www.facebook.com/wikipedia/
Both Instagram and Facebook have the apple-app-site-association files in place in the root of their websites. What should I do to make the link to the Facebook Wikipedia profile open the app as well and is the behaviour when the app opens the result of Universal Linking or something else?
PS: I'm hesitant to use custom URL schemes (e.g. fb://profile /XXX) since they don't degrade nicely if the app isn't installed. Prompting the user for a choice is an acceptable solution to this problem which, however, instead introduces confusion when the app is sometimes opened even if the user has made the choice to go to the web version (this would be the case for any of the first three links above).