Couldn't this be solved by uploading the binaries along with the crash dumps, if you don't already have a copy of it, as determined by checking hashes or something?
Do you have a specific example of which executables are missing?
There are also other ways to get all the debug symbols but it’s much fiddlier and not nearly as nice as debuginfod. Data’s all there, finding it is harder. You can query the apt index for buildids but only for the currently released package version and not superseded ones.
There were discussions about importing all the history and a way to do it was determined but not sure where the implementation of that has gotten too.