Apple asks you if you want to keep or cancel your subscription when you uninstall an app that has an active sub. There’s also several entry points to the UI, including from the App Store and Settings. Ideally there’d be a deep link option for other apps to link into it, but I’d say Apple clearly has a better experience and makes it easier to cancel these subscriptions.

https://ibb.co/JBz5Rgh

Definitely correct: I didn't remember how to access them (I actually did it in the past, but forgot exactly how. My point still stands, I believe: it's too hard, not prominent enough. In particular I was disappointed by the "Manage subscriptions" link that brought me to a screen where I could not do that.