Thank you for your continued feedback. We have a feature on the backlog for popping out content, so that you can see one screen with the video gallery and one screen with the shared content. We will share an update as soon as one is available.
For the separate feature ask for full screen option, please upvote and comment at https://microsoftteams.uservoice.com/forums/555103/suggestions/41277121.
For split screen camera and desktop, please upvote and comment at https://microsoftteams.uservoice.com/forums/555103/suggestions/37118773.
For full screen for self video, please upvote and comment at https://microsoftteams.uservoice.com/forums/555103/suggestions/38322247.