The CL 46294798 added changes to Horde.sln and HordeServer.csproj files, which are totally unrelated the content of the CL itself, but these changes broke the builds, as those are now referencing to Epic internal files. Could you please undo those on ue5-main?
EDIT: I have added a pull request to GitHub for this to clarify what I mean:
https://github.com/EpicGames/UnrealEngine/pull/13946