X.app features 2 extensions for changing video mode:

App Store download link:

Picture-in-Picture Video Extension activates PiP in all apps on iPhone and iPad:

Fullscreen Video Extension

Besides Picture-in-Picture Extension, X.app also contains a Fullscreen Video Extension, which has 2 purposes:

App Store download link: https://apps.apple.com/app/id1533525753

Native Fullscreen UI

Sites and apps like YouTube…

Get the Medium app

A button that says 'Download on the App Store', and if clicked it will lead you to the iOS App store
A button that says 'Get it on, Google Play', and if clicked it will lead you to the Google Play store