Gnome 40 and maximized windows / fullscreen apps

[KShots]

I've got mulitple apps that won't maximize or go full-screen now that I've updated to gnome 40. These include steam streaming titles and the unreal engine editor (very frustrating, that). Below is a screenshot of a steam streaming instance that won't go full screen. Note that the initial splash during the streaming connection does go full-screen, but once connected, it drops back to what's pictured below. The server and client are both running at 3440x1440 resolution, with the client monitor set to 3440x1440 on that display. Used to work fine on pre-40 gnome.

Steam streaming issue

The unreal engine editor shows maximize/minimize buttons, but refuses to maximize when pressed. Minimize works. The window cannot be moved from its initial position (click+drag does nothing). When closed and re-opened, all is well (maximize works, click+drag works). When closed and re-opened again, it breaks again. This cycle repeats in a predictable fashion (off-on-off-on-off...). Quite frustrating as the editor frequently crashes or needs a restart to sync with the IDE, and each restart takes about a minute and a half. This cycling does not work with steam streaming - it always breaks.

Any idea where to look to start figuring out what broke and why?
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