Currently, the “Toggle collision fidelity” option is way too unintuitive to find in the Customize Shortcuts menu, to the point where community members I’ve spoken to install additional plugins in order to bind it to a hotkey, because they assume Studio does not support it.
This could be attributed to it having a different name compared to the Settings menu:
(Note that it is not bound to any key, not even O, by default, I just couldn’t figure out to how reset the shortcut after testing it.)
Searching “decomp” or “geo” in the Customize Shortcuts menu does not bring up the desired action. It also does not appear unless you have a Place file open, which I don’t fully understand the rationale of given that the menu still displays other shortcuts which are still only relevant when inside a Place. All of these minor things contribute to making this unusually difficult to find for people who just want a hotkey to toggle a Studio setting.