Bump! Everything I see is "use the Edit Scheme -> Run -> Arguments -> Environment variables" but this is not what I want since the value has to be specified there. So...?

Also had the same problem (xCode 13.0 beta 5 (13A5212g) ) only with types that are available from iOS13. Managed to workaround it by increasing the iOS deployment target to 13 of submodule, which in turn asked to increase the project iOS version, which gave a lot of warnings but no errors, so I was able to build my App and test it. This works for me now, but definitely not a right solution, just a temporary. Lets hope for the fix in the next release.