Did you build from source? The cmake script downloads from this SDL_GameControllerDB link which seems correct. There is a custom target
update_mappings which needs to be built, which updates
src/mappings.h. This works for me.
The source release for 3.3.5 also appears to contain a
src/mappings.h file with a long list of mappings - I’ve not checked the binary releases but they should have been built from this source. If you see them missing let me know which binary version you’ve got so I can check that.
If you are missing a particular GUID, and if it’s missing in SDL_GameControllerDB then it should be submitted to that repo.