Despite not mentioning it during the presentation, Apple is bringing the option to select default browser and email app with the new iOS 14 and iPadOS 14 update. You will now be free to ditch Safari and the native Mail app and select alternatives which will open links and compose messages.
The new feature is part of the detailed key features and enhancement breakdown on Apples website. Developers will need to optimize their apps to support these new features and browsers will still be forced to rely on Apples WebKit engine.
Previous rumors suggested that Apple might bring a similar change for music apps but at least for now, this is not happening.