Yes, an option with an easy-to-access button on the top toolbar would be great for this (it's similar to what TV has). And just to be clear, what I'm talking about is something that disables catching any non-standard keys, so, for example, Alt+Tab and the Media keys would have a local effect.
The remote-desktop-like option could also be implemented in the settings: adding an option to disable capturing such keys when not in full-screen mode.
Well, the thing that I'm missing is some way to avoid sending "special" keys to the remote when I work with a single remote thing and local applications. With the default windows remote desktop I get that when the viewer is not full-screened; with [censored] there's a toggleable option to send special keys to the remote or not. I was surprised that there is no such option with RU (at least AFAICT).
I tried unbinding all of the full control hotkeys (Options -> Hotkeys -> set all to "None"), but then I get a complaint that "Hot keys must be unique" -- I'm guessing that there's some bug where "None" entries are counted as keys for the purpose of uniqueness.
I find the "Q" thing very inconvenient... The purpose is, AFAICT, to make it easier for people who use the keyboard more than the mouse, and as such a person I'm usually working in some window where "Q" *will* do something.
FWIW, the model that I found most convenient is the windows remote desktop thing: no "special keys" are captured remotely unless I'm in full-screen mode. This means that I can either do that for completely remote working, or switch to a regular-but-maximized window when I want to interact with a single window remotely together with the rest of my local windows.