So either every user needs to manually bind every command using their WM's bespoke global hotkey mechanism, or the developer needs to ship keybinds for every possible WM.
Sounds like a nightmare for everyone involved to me
I think you've got it backwards. Applications like OBS do not typically register default global keybindings to avoid clobbering, you have to do it manually in their settings menu. The only difference with a generic interface is that the dialogue opened from the setting menu would be from the WM instead of OBS.
The problem with Wayland in this respect is that there is no such generic interface that works everywhere - each compositor may choose not to support it at all, or support it in different ways.
If there was a single standard way, great. In the meantime I'll stick to X11, which isn't this incredibly user-hostile.
That is not a problem with Wayland because specifying this is not a within the purview of Wayland. People like you don't seem to understand that Wayland is specification, and not an implementation like X11.